Allow sheets which use SSSelectableToolbar to remember their size per tab

Right now the size of each tab is derived solely from the base size contained in the XIB on loading. This means if the view is resizable, on opening the sheet for a second time, the last used size is not remembered. Switching tabs while the sheet is open does remember the size.

Perhaps we could detect if the parent window has an autosave name, and if so derive a prefs setting name for each tab (if the window is resizable) which is then used to derive the window size on opening instead of the default size. This would then have to be manually saved when the window is closed.

Will definitely be a change to SSSelectableToolbar, but the sheets affected are:

• Settings sheet
• Create Patch sheet
• Apply Patch sheet