use cleaner representation of resolution in save files

[pkienzle]

Capturing the resolution in a single resolution tag would be a cleaner internal representation than simply dumping the fields on the fit page form. Currently resolution is spread across:

	<enable_smearer enable_smearer="False"/>
	<disable_smearer disable_smearer="False"/>
	<pinhole_smearer pinhole_smearer="True"/>
	<slit_smearer slit_smearer="False"/>
	<smearer smearer="&lt;sas.sascalc.data_util.qsmearing.PySmear object at 0x116867d90&gt;"/>
	<smear_type smear_type="None"/>
	<dq_l dq_l="0.00109"/>
	<dq_r dq_r="0.02375"/>
	<dx_max dx_max="0.005"/>
	<dx_min dx_min="0.003"/>
	<dxl dxl="0.0"/>
	<dxw dxw=""/>

The following attributes appear to be unused:

	<smearer smearer="&lt;sas.sascalc.data_util.qsmearing.PySmear object at 0x118367310&gt;"/>
	<smear_type smear_type="None"/>

As well as being very bad style (the object when it is reloaded will no longer be at 0x1183c7310 so no reason to store that information), they remain the same regardless of which resolution options are chosen. The model still loads with the same resolution options as it was saved with.