- Added NxM size matrices
- Added unsigned int uniforms
- Removed dead code(packVaryings) in Program

Change-Id: I0ecb47fa468245f60b9aa026d07fa9ed1f871340
Reviewed-on: https://swiftshader-review.googlesource.com/2745Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>