Merge pull request #3 from EmilWestergren/master

Implemented stride for OpenGL textures and shaders for drawing overlay lines
Removed ancestors and made GpuPacker a single class
Changed name to EglRgba
Removed old EGLImage class (renamed)
Added parameters to creation of egl image
Adapted to changed GpuPacker
Added packer for packing a downscaled image
Fixed error