Update stb_image.h (#32)

* stb_image: Fix zlib decoder end-of-stream handling

This commit applies the patch from [stb_image@d373674](nothings/stb@d3736741151fd76cf8deccb9e94d4d83da3d3e4eA).

* stb_image: Small PNG filter simplification

This commit applies patch from [stb_image@e5f0e18](nothings/stb@e5f0e18).

* stb_image: New Paeth filter

This commit applies patch from [stb_image@07268cb](nothings/stb@07268cb).

* stb_image: create_png_image_raw restructuring

This commit applies patch from [stb_image@4da08a1](nothings/stb@4da08a1).

* stb_image PNG: Checks for invalid DEFLATE codes.

This commit applies patch from [stb_image@9f22cc9](nothings/stb@9f22cc9).

* stb_image: Merge branch 'neilbickford/image_hdr_pgm_fixes'

This commit applies patch from [stb_image@e5da6ac](nothings/stb@e5da6ac).

* stb_image: Fix name of stbi_set_unpremultiply_on_load_thread impl

This commit applies patch from [stb_image@4d160de](nothings/stb@4d160de).

* stb_image: Merge branch 'NeilBickford-NV-neilbickford/additional-image-fixes'

This commit applies patch from [stb_image@b15b043](nothings/stb@b15b043).

* stb_image: Avoid stdint.h on 32-bit Symbian.

This commit applies patch from [stb_image@038b6ab](nothings/stb@038b6ab).

* stb_image: Add trailing semicolon to usage example

This commit applies patch from [stb_image@51d295e](nothings/stb@51d295e).

* stb_image: Accept some extra data between BMP header and payload

This commit applies patch from [stb_image@1096389](nothings/stb@1096389).

* stb_image: Tweak end-of-JPEG junk scanning loop.

This commit applies patch from [stb_image@0613e9c](nothings/stb@0613e9c).

* stb_image: header scan mode always needs to check for tRNS

This commit applies patch from [stb_image@40eb865](nothings/stb@40eb865).

* stb_image: a fix

This commit applies patch from [stb_image@1891060](nothings/stb@1891060).