ZDoom language configurations update
- DECORATE:
  - Added FPF_AIMATANGLE and FPF_TRANSFERTRANSLATION constants for A_FireCustomMissile.
  - Updated A_FireCustomMissile's syntax to replace 'aim' with 'flags'.
Merge pull request #173 from Blue-Shadow/master

ZDoom language configurations update
Fix crash on moving a vertex in a map with no lines
Add typed characters to browser filter rather than searching when canvas is focused
Add check for WMP installation in Windows

Disables soundfont-less MIDI and MP3 playback if not installed
Clear scripts on creating new map
Fix possible crash after saving map while in 3d mode
Don't use refresh timer for OGLCanvas when not using SFML RenderWindow

Seems to cause stuttering in the map editor if another OGLCanvas is showing (eg. the map preview in the main editor  window)
Add new archive to recent files on map 'Save As' (or saving a new map)

Also hopefully fixed up focus issues when executing an external program, ie. when building nodes
Merge branch 'master' of https://github.com/sirjuddington/SLADE into osx