Adds support for Android.

This has been tested with both OpenGL and OpenGL ES on Android.
We can't use dlsym on Android to get all the function pointers since Android's libGLES* libraries are just shim libraries that pass everything through
to the real vendor specific libraries.

Due to this we must grab function pointers entirely through eglGetProcAddress instead of dlsym.
Merge pull request #27 from Sonicadvance1/Android-Support

Add support for Android.
Remove a C99ism from dispatch.

I've decided it's time to accept that building with MSVC 2010 is a way
that people want to use this software.
Add a control file for Travis CI.

This isn't quite as good as I'd like -- the XVFB setup doesn't support
a bunch of context creation extensions that we use, and I haven't
looked into the multiplatform stuff for doing OS X testing yet.  I
think it's a good start, though.
tests: Fix the passing of the "-z now" arg to the linker.

These LDFLAGS go to the compiler, and getting the arg to the linker
requires -Wl or -Xlinker.  gcc apparently was passing this through
anyway, while clang was getting angry.
Use the EGL pkgconfig for finding eglplatform.h.

We don't ever explicity link against libEGL, so no need to make use of
EGL_LIBS.

Fixes #30.
Fix context type detection if we find eglGetCurrentContext().

Fixes #29.
Avoid name conflicts between pkgconfig's EGL_LIBS and a temporary var.

I felt a little uncomfortable knowing I had two things defining
EGL_LIBS, but it worked on my system.  It failed on the travis ci
build.