Test01:- Copes with resizing windows. The orthogonal rectangle now displays in the middle of the screen at all times.
Merge branch 'master' of https://github.com/MarkIngramUK/glow

* 'master' of https://github.com/MarkIngramUK/glow:
  Glow:- Texture, added SetData method.
Merge branch 'master' of https://github.com/MarkIngramUK/glow

* 'master' of https://github.com/MarkIngramUK/glow:
  Glow:- Added FramebufferObject and FramebufferObjectSession (unlike most other GL objects, a FramebufferObject doesn't have a "default" object, so binding to zero can mess things up, the window system FramebufferObject might be ID = 2 for example). - Debug, only perform error checking in debug (else it's too slow). - Texture, added an IsBound function which is used by FramebufferObject (attaching a texture to a framebuffer can't use an already bound texture). - VertexArrayObject, added error check in destructor - Added make_unique (until we've got C++14 support).
  Glow:- Mac, added File class and Glow initialisation to the project. - Program, glBindFragDataLocation is only available in GL, not GL ES.
Glow:- Matrix, removed this class as it doesn't actually wrap any GL functionality. Instead use the Matrix class in m3d.
- Texture, removed any knowledge of texture units. This simplifies things for when you don't need more than one texture unit and for cases where you do, use:
- TextureUnits, new class which manages bindings of textures to texture units. Also maintains state to avoid unnecessary GL state changes.