Should compile under Windows again

git-svn-id: http://svn.code.sf.net/p/irrlicht/code/branches/ogl-es@4595 dfc29bdd-3216-0410-991c-e03cc46cb475
Abstract away the EGLManager into IContextManager and add the manager for win32/ogles1 as well.
Android device should still compile and work, but was not tested.

git-svn-id: http://svn.code.sf.net/p/irrlicht/code/branches/ogl-es@4596 dfc29bdd-3216-0410-991c-e03cc46cb475
Fixed OGL-ES2 for win32 as well. Not yet properly running with my emulator, though. So setup might still be incomplete here.

git-svn-id: http://svn.code.sf.net/p/irrlicht/code/branches/ogl-es@4597 dfc29bdd-3216-0410-991c-e03cc46cb475
- Removed warnings related to unsupported E_COLOR_FORMAT in switch-case.
- Fixed Android compilation issues.
- Marked Android input and command static methods as public (it's useful for custom versions of these methods).

git-svn-id: http://svn.code.sf.net/p/irrlicht/code/branches/ogl-es@4599 dfc29bdd-3216-0410-991c-e03cc46cb475