Updated README.md
Fixed issue where attribute offsets were incorrect
Shader constructor fix

Fixed issue where using the shader constructor to set uniform defaults
was subject to a macro race condition. Setting uniforms *after* super()
is now safe :)
Fixes to shader inheritance and texturing
Snow compatibility fixes
Adding dirty flags to uniforms

Still need to figure out a smart way to update them though, without
asking the user to manually setDirty.
Support for samplerCube

Also made changes to support multitexturing better, though it's a bit
shitty right now :P
@color annotations for vec3/4 unis

Contextually creates UColor3/4 abstracts instead of raw UVec3/4
UFloat clamping and material factory