-Changed the state controller forcing the user to specify the needed pointers

Added the class State to the framework in order to manage combinations of VertexBuffer, FrameBuffer and ShaderProgram.
The class automatically creates a mapping between the attributes of vertexbuffers and shaders.
Furthermore a mapping between FragDatas of shaders and rendertargets of framebuffers are created.

call glBindFragData(...).
The RenderTargets of a FBO can now be named.
Furthermore every occurence of 'aPosition' has been changed to 'iPosition' etc. for aColor, aNormal..

Started to constify everything. The FileManager now returns a ConstSharedResource to prevent changes.

Removed static contexts from the opengl object. In future, this has to be handled by our opengl wrapper, which will hold a copy of the gl state on cpu side.
Made all opengl contexts not copyable.
Created a macro for the shared typedefs which directly creates a const version of the pointer.
Started to change some opengl object functions to be non-const although they might not change any class members, because the function still might change something on gpu side. Therfore, returning the context of any opengl object is also non-const now!
Changed the renderbuffer constructor to just create the context and moved the rest to its corresponding controller.
Removed own type enums in opengl objects => ONLY use the orginial GLenums here!

Until now only the class Texture used it. Now it has been added to ElementArrayBuffer, ArrayBuffer, FrameBuffer and ShaderProgram.
Static class members have to be initialized outside the header, so the file ElementArrayBuffer.cc had to be added.
Unbind calls e.g. glBindBuffer(GL_ARRAY_BUFFER, 0) outside of the specific class are not useful anymore, because it
would not reset the static context variable and thus lead to bugs/crashes.

shader attributes are now bound by their occurence in the shader source (just before linking the program)