Bug fixes and small feature adds

- Expand custom geom #include statements and save with geom
- Added GetCustomXSecLoc/Rot
- Increased size of Custom Screen
- Added GDEV_SCROLL_TAB
Merge branch 'master' of https://github.com/ramcdona/PrivateVSP
Update Geom Browser FLTK: add some buttons, beautify, make more consistent.
Add 'None' surface shade mode.
Clarify name of Vehicle::ShowOnlySet method
Add show and noshow set buttons and Vehicle methods.
Add SelectSet button functionality to Geom Browser
Refactor CutGomVec to pull out code for later re-use.
Implement Vehicle DeleteGeomVec methods.
Add Delete button functionality to Geom Browser
Tighten up Geom Browser by removing vertical gaps.
Make Geom Browser shorter and wider to Bill's suggestion.