py3 support for 4.x series

[pkienzle]

SasView 4.3 will run on python 3.x with wx 4.x, but it hasn't been extensively tested. Need to test that the various dialogs function correctly, and make sure that file I/O works.

Here's a list of file open calls in the code:

$ grep -r "\\bopen[(]" src | grep -v [.]open | grep py:
src/examples/data_generator/testdata_generator.py:        fd = open(filename, 'w')
src/sas/_config.py:    if not "SAS_OPENCL" in open(path).read():
src/sas/_config.py:            open(config_file, "a+").write("SAS_OPENCL = \"None\"\n")
src/sas/sasgui/perspectives/invariant/report_dialog.py:            f = open(fName, 'w')
src/sas/sasgui/perspectives/invariant/report_dialog.py:        f = open(fName, 'w')
src/sas/sasgui/perspectives/invariant/invariant_state.py:        html_template = open(path_report_html, "r")
src/sas/sasgui/perspectives/invariant/invariant_state.py:            fd = open('test000', 'w')
src/sas/sasgui/perspectives/invariant/invariant_state.py:            fd = open(filename, 'w')
src/sas/sasgui/perspectives/fitting/basepage.py:            input_f = open(path, 'r')
src/sas/sasgui/perspectives/fitting/basepage.py:        with open(categorization_file, 'rb') as f:
src/sas/sasgui/perspectives/fitting/report_dialog.py:            with open(filename, 'w') as f:
src/sas/sasgui/perspectives/fitting/report_dialog.py:            with open(filename, 'w') as f:
src/sas/sasgui/perspectives/calculator/resolution_calculator_panel.py:            input_f = open(path, 'r')
src/sas/sasgui/perspectives/calculator/model_editor.py:        with open(self.fname, 'w') as out_f:
src/sas/sasgui/perspectives/calculator/model_editor.py:        out_f = open(fname, 'w')
src/sas/sasgui/perspectives/pr/inversion_state.py:            fd = open(file, 'w')
src/sas/sasgui/perspectives/pr/inversion_state.py:            fd = open(filename, 'w')
src/sas/sasgui/perspectives/pr/pr.py:            input_f = open(path, 'r')
src/sas/sasgui/perspectives/pr/pr.py:            input_f = open(path, 'r')
src/sas/sasgui/perspectives/corfunc/corfunc_state.py:            fd = open(filename, 'w')
src/sas/sasgui/perspectives/corfunc/corfunc_state.py:        fd = open(filename, 'w')
src/sas/sasgui/perspectives/file_converter/converter_panel.py:            f = open(filename, 'r')
src/sas/sasgui/guiframe/config.py:            out = open(__EVT_DEBUG_FILENAME__, 'a')
src/sas/sasgui/guiframe/report_dialog.py:            resultFile = open(filename, "w+b")
src/sas/sasgui/guiframe/startup_configuration.py:        with open(path, 'w') as out_f:
src/sas/sasgui/guiframe/CategoryInstaller.py:            with open(serialized_file, 'rb') as f:
src/sas/sasgui/guiframe/CategoryInstaller.py:            json.dump(master_category_dict, open(serialized_file, 'wb'))
src/sas/sasgui/guiframe/CategoryManager.py:        cat_file = open(CategoryInstaller.get_user_file(), 'wb')
src/sas/sasgui/guiframe/CategoryManager.py:                with open(cat_file, 'rb') as f:
src/sas/sasgui/guiframe/gui_manager.py:        fd = open(file_name, 'r')
src/sas/sasgui/guiframe/gui_manager.py:            fd = open(file_name, 'w')
src/sas/sasgui/guiframe/gui_manager.py:            fd = open(temp_file_name, 'w')
src/sas/sasgui/guiframe/gui_manager.py:                fd = open(fName, 'w')
src/sas/sasgui/guiframe/gui_manager.py:            config_file = open(custom_config.__file__)
src/sas/sasgui/guiframe/gui_manager.py:            new_config_file = open(custom_config.__file__,"w")
src/sas/sasgui/guiframe/gui_manager.py:            out = open(path, 'w')
src/sas/sasview/local_config.py:            out = open(__EVT_DEBUG_FILENAME__, 'a')
src/sas/sascalc/calculator/sas_gen.py:            input_f = open(path, 'rb')
src/sas/sascalc/calculator/sas_gen.py:            input_f = open(path, 'rb')
src/sas/sascalc/calculator/sas_gen.py:                input_f = open(path, 'rb')
src/sas/sascalc/calculator/sas_gen.py:        out = open(path, 'w')
src/sas/sascalc/fit/models.py:    out = open(PLUGIN_LOG, 'a')
src/sas/sascalc/fit/Loader.py:            input_f =  open(self.filename, 'r')
src/sas/sascalc/fit/pagestate.py:            fd = open(file, 'w')
src/sas/sascalc/fit/pagestate.py:        fd = open(filename, 'w')
src/sas/sascalc/pr/fit/Loader.py:            input_f =  open(self.filename, 'r')
src/sas/sascalc/pr/num_term.py:        input_f = open(path, 'r')
src/sas/sascalc/pr/invertor.py:        file = open(path, 'w')
src/sas/sascalc/pr/invertor.py:                fd = open(path, 'r')
src/sas/sascalc/file_converter/bsl_loader.py:        header_file = open(filename, 'r')
src/sas/sascalc/file_converter/otoko_loader.py:        with open(header_path, "r") as header_file:
src/sas/sascalc/file_converter/otoko_loader.py:            with open(info.file_path, "rb") as binary_file:
src/sas/sascalc/file_converter/cansas_writer.py:        file_ref = open(filename, 'w')
src/sas/sascalc/file_converter/ascii2d_loader.py:        with open(self.data_path, 'r') as file_handle:
src/sas/sascalc/file_converter/red2d_writer.py:        fd = open(filename, 'w')
src/sas/sascalc/dataloader/file_reader_base_class.py:                    self.f_open = open(filepath, 'rb')
src/sas/sascalc/dataloader/readers/cansas_reader.py:        file_ref = open(filename, 'wb')
src/sas/sascalc/dataloader/readers/red2d_reader.py:            fd = open(filename, 'w')