[Rewrite] Cast int32 overloads to native int

Int32 parameters should be converted to native int when
the native signature expects the latter.
[Bind] Add int overloads to buffer size (IntPtr) parameters

As a convenience, int overloads are provided for IntPtr size
parameters (corresponding to BufferSize or size_t). In the vast
majority of cases, a 32bit int is sufficient for buffer sizes,
so these overloads avoid the necessity of annoying (IntPtr) casts.

If more than 2^31-1 elements are required, the IntPtr overloads
remain available. (As always, this requires a 64bit runtime
environment.)
Merge pull request #172 from thefiddler/intptr_fix

[Rewrite] Cast int32 overloads to native int
[GL] Added int overload to DrawElements for OpenGL4
[Build] Update Travis CI to mono 3.6.0
Merge pull request #175 from thefiddler/mono360

[Build] Update Travis CI to mono 3.6.0
Merge pull request #174 from thefiddler/issue171

[GL] Added int overload to DrawElements for OpenGL4
Merge pull request #173 from thefiddler/buffersize_to_int

[Bind] Add int overloads to buffer size (IntPtr) parameters
[GL] Added ARB_clip_control
[GL][ES] Added tokens for backwards compatibility

The 4.5 spec moves BLEND_ADVANCED_COHERENT_KHR from
KHR_blend_equation_advanced to KHR_blend_equation_advanced_coherent.
Add a deprecated token to maintain binary compatibility.
[GL] Implemented ARB_cull_distance
[GL] Implemented ARB_conditional_render_inverted
[GL][ES] Implemented KHR_context_flush_control
[GL] Implemented ARB_get_texture_sub_image

Also fixed KHR_context_flush_control tokens in OpenGL ES.
[GL][ES] Implemented KHR_context_robustness
[GL] Added missing tokens for 4.2-4.4
[GL] Implemented ARB_direct_state_access

See http://www.opengl.org/registry/specs/ARB/direct_state_access.txt
[Bind] Allow multiple overrides files

Multiple overrides files allow us to split overrides by extension,
simplifying maintenance.
[GL] Added a missing enum
[Bind] Moved GL overrides to parent folder