added new graph style
Fix texture completeness for non-POT textures on GLES2/WebGL
Merge pull request #156 from floooh/pr_clamp_to_edge

Fix texture completeness for non-POT textures on GLES2/WebGL
Merge pull request #148 from pupil-labs/master

added new graph style
Fix for issue #155

- added NVG_DEBUG which can be used to omit calls to glGetError()
- removed return value for glnvg__checkError
- create flag defines to enum
Merged upstream changes