Fixed comma at the end of enumeration list.
GCC 4.6 compatibility: weird name conflicts. WTF.
Moved BufferTextureFormat enum before the class.

Just to make merging into the compatibility branch easier.
SceneGraph: use `virtual` where it hurts less.

Having `virtual` destructor in less templated base is better than having
it repeated in five times more subclass specializations.
Shapes: simplified collision dispatch implementation with macro.
Shaders: use Context::isVersionSupported() instead of ad-hoc solution.

Also removed redundant branching for ES.
Shapes: overlooked `typename`.

Spotted by good ol' GCC 4.4. Newer compilers don't bother with that
verbosity at all.
Oh yeah, coding while drunk.

F'ed up in c2a5919b5a7f78dbcf280a3dff2ec15dac7b12dc.
NaCl's newlib doesn't have std::to_string().