Remove GLEW dependency; improve GLES1 usage.

Remove dependency on GLEW.  It was used in precisely one place in
FBO.cpp.  It has been replaced with a partial substitute which correctly
interrogates for framebuffer object support in GLES, but doesn't yet
hook up the functions that call it.  More work needs doing here, as GL
1.1 has EXT and ARB extensions, GLES1 has an OES extension, and GL 2.0+
and GLES2 provide support directly.

Fix up places where GL (as opposed to GLES) headers were still included
despite specifying USE_GLES1.

GLES doesn't have glRect.() functions; implement glRectf().  Hopefully I
got the state preservation correct.

Convert use of glInterleavedArrays() to glVertexPointer() and

Disable compressed texture support in SOIL.c -- GLES2 only supports DXT1
as an extension, and GLES1 doesn't have it at all.

After this changes, the thing compiles.
10 files changed