Added a member function to extract the uniform names from GLSL

|SOURCE|
[Common/Shader]
* Renamed LoadShaderFromSource to CreateShaderFromSource to better reflect the
  function's intent
* Added a private member function to extract uniform names from GLSL and store
  them in the map along with a null location ID, the shader code is assumed
  valid and passed through glCompileShader with no problems
* CreateShaderFromSource reads GLSL either from a file or from memory and
  compiles it to usable object code, minimal error checking is performed