Fixed a possible crash when rendering thing arrows in classic modes caused by incorrect vertex buffer size calculation.
Reverted changes to texture\flat access when "mixtexturesflats" option is set to true in game configuration.
Script editor: pressing "F1" now opens keyword help instead of program manual.
Linedef edit form, Thing edit form: rewritten script support logic. It should now work in the same manner as the rest of controls.
Thing info panel: thing arguments now have proper labels.
Edit forms, UDMF: fields, which are handled by UI, are no longer shown in "Custom" tab.
Visual mode: fixed a crash when loading a model on a video card without Shader model 2.0 support.
Fixed incorrect argument number and changed most of labels in "Cameras and interpolation" section of zdoom_things.cfg.
