BACKENDS: Remove OpenGL and OpenGL SDL backend.

This breaks our Tizen port.
BUILD: Mark ZVision as requiring freetype2/16bit
ZVISION: Consistently use the type of the state map

Should fix the AmigaOS4 build
ZVISION: Make the line height be an int
WINTERMUTE: Remove useless __inline
ZVISION: Attempt to fix compilation on AmigaOS4
FULLPIPE: Plug resource leak. CID 1107570
DRACI: Fix negative array index read. CID 1003548
DRACI: Initialized class variables. CID 1003405
DRASCULA: Initialize class variables. CID 1003403
DREAMWEB: Initialize few more class variables. CID 1003402
TOUCHE: Initialize uninit variables. CID 1002423
FULLPIPE: Implement MovGraph2::findMinPath()
TSAGE: Bugfixes for voice playback to work in conversations
FULLPIPE: Implement MovGraph2::buildMovInfo1SubItems()
FULLPIPE: Implement MovGraph2::findLink()
TSAGE: Fixes for allowing selecting speech in the ScummVM options dialog
FULLPIPE: Fix crash in MovGraph2::buildMovInfo1SubItems()
OPENGL: Add new generic OpenGL (ES) backend.

This backend is based on ideas of the old OpenGL backend, of the Android GL
backend and of the iPhone GL backend.
SDL: Add a OpenGL SDL backend and hook it into the SDL backend.

The hooking code is nearly exactly the old hooking code. Only the OpenGL SDL
creation has been adapted since it uses a different constructor now.