Merge pull request #79 from cforfang/master

Set glFrontFace in glnvg__renderFlush
Fixed issue #80

- increased initial buffer sizes
- change all allocator patterns to over allocate by 1.5x
- fixes bug where nvgl back-end was not allocating +n as requested
More error checking on allocations

- changed remainder of allocations to follow same 1.5x patters
- do not leak memory when realloc() fails
- added error handling in case allocations fail
Fix for issue #78

- use one not used macro for all
Fix to update alloc count after successful alloc