Reset pixel storage settings after load texture.

Improve VC support

Remaining change for VC support

- Renamed FPScounter to PerfGraph
- dump avg times at exit

- moved performance counter and drawing to separate file
- tweaks to performance drawing

Support for cases where the gl header does not include GL_ARB_TIMER_QUERY

Quick guard against NULL ptr dereference of texture type on CPU side

Timing for CPU inner frame and GPU inner frame added

Needs names for the UI components to distinguish them, and probably stacking vertically for easier comparison.

- implemented missing scissor from draw triangles
- buffer a whole frame of uniforms
- moved paint to uniform conversion earlier
- simplified render loops and data structures
- renamed bunch of things
- combined shaders, use define to disable AA

- correct fix for ubo memroy allocation (use returned alignment instead
of struct size)
- separated convex fill to own command type
- moved uboPos to call struct

Added glMapBuffer cast

Cast void* to char* to remove compiler warning in C++ project in VS2013

Fixed some warnings with MS compiler

Moved nanovg_gl3buf.h to uniform buffers

Win32 modification to get code to run, and performance increase for buffered gl3

STBI_NOTUSED

- removed assize from the back-end api
- moved image to paint in renderTriangles call

- added NVG_NOTUSED to suppress unused param warnings
- fixed scissor anti-aliased border width when zoomed

Added float cast to viewport size

stdio.h

Added float cast to remove compiler warnings.