fix nvgCreateImageFromHandle for GLES2/3.
API changed! Fixed slowdown, Shader uses premultiplied colors

- all colors in the shader is handled as premultiplied
- removed alphaBlend param from nvgBeginFrame(), it became obsolete
- added NVGL_TEXTURE_PREMULTIPLIED flag
- separated FBO example
- FBOs are treated as premultipied for correct alpha
- changed FBO storage from depth/stencil 24/8 to stencil 8
- moved discard to end of shader which restores the render speed again
Fix for issue #111

- added nvgQuadTo, draws quadratic bezier curve segment
Fix for issue #108

- fixed stroke cap tessellation amount calculation
Merge pull request #104 from starwing/master

fix nvgCreateImageFromHandle for GLES2/3.
Removed unused mu variable
Changed not used macro from do {} while(0), to for(;;) { ... break; }
Fixed memory leak
Fixed potentially uninitialized local variable warning
Fixed missing void in function with no parameters
Merge pull request #115 from cforfang/small_fixes

Memory leak + small fixes
Removed unused mx,my,len
second attempt at avoiding warnings at /W4 on vs2013
use -1 as the 'no scissor' value, rather than 0, so that 0 width still scissors
clamp on scissor, fix nvgReset
Merge pull request #121 from sgraham/zero-w-scissor

use -1 as the 'no scissor' value, rather than 0, so that 0 width still scissors
Merge pull request #120 from sgraham/warnings-attempt-2

second attempt at avoiding warnings at /W4 on vs2013
Font stash: store pref glyph as index instead of pointer
Added mipmap generation option - useful for clients that need images with mipmaps for better quality scaling.
Tweaked premake to remove some windows warnings.
Also set the mipmap flag for GL ;)