Using GLEW for OpenGL extensions and started work on getting vertex attributes

|SOURCE|
[Common/PolygonCache]
* Added a set of member variables for the vertex attributes
* Added a member variable for the vertex array object, which is applied for the
  entire cache
* Added a member variable for the stride of the vertices in the cache
[Common/Game]
* GLEW is initialised, if it does not initialise properly, then a fail state is
  returned