Merge branch 'opengl-boxes' into development
Added PNG++ source to the tree
Created class Image which loads PNG

`Image` is a simple class that loads a png and stores it. It has width,
height and the raw data. The data is always RGBA tightly packed.
Created macro to delete method

On compilers that support the `= delete` syntax it is used. On msvc,
the method is privated and it's implementation is just a call to abort.