Fixed, DECORATE parser: enums were not handled properly.

General interface: selection info is now always displayed.
Visual mode: you can now hold Alt-Shift or Ctrl-Alt while selecting sidedefs to stop selecting connected sidedefs when already (un)selected sidedef is encountered.
Added, Numeric Textbox: you can now use "+++" and "---" prefixes to incrementally increase or decrease result values by given value.
Fixed, Numeric Textbox: fixed a potential divide by zero exception when using "/" prefix in numeric textboxes with decimal input enabled.
Fixed, Thing Info panel: relative z position of things with "+SPAWNCEILING" flag was incorrect.
Changed: Update checker now displays messages using MessageBoxes when called manually.
Map Analysis: changed result descriptions for Unknown Texture and Missing Texture checks.
Doom map format: renamed "Secret" linedef flag to "Shown as 1-sided on automap".
Updated ZDoom_DECORATE.cfg (A_RadiusGive stuff).