- LoadFontDefault() -> Some code simplifications
 - LoadFontFromImage() -> Avoid LoadImageEx()
 - LoadFontData() -> Avoid GenImageColor(), ImageFormat()
 - LoadBMFont() -> Avoid ImageCopy(), ImageFormat()

Removed ImageAlphaMask() dependency on [text] LoadBMFont()

Most warning were related to types conversion (casting required) and unsigned/signed types comparisons.

Added preprocessor directives (_CRT_SECURE_NO_DEPRECATE; _CRT_NONSTDC_NO_DEPRECATE) to avoid warnings about unsafe functions, those functions are safe while used properly and recommended alternatives are MS only.

Some external libraries still generate warnings.

There are multiple #define values around raylib, usually not exposed for redefinition, just reviewed all of them to allow users redefining them on compile time if required.

Also, multiple #define have been renamed and commented.

- Added NULL return if the replacement string (`by`) is empty
- Reordered sanity checks since there's no need to initialize variables if the strings are invalid.

* Fixed offset check in GenImageFontAtlas

* Fixed code formatting to follow raylib notation rules

Using new file I/O ABI

This issue was breaking multiple things...

Just for clarification, no plans to remove libc dependency, just did some code analysis to see how much raylib depend on stardard C library. My conclusions:

 - stdlib.h: primary dependency is for malloc() and free()
 - stdio.h: primary dependency is for FILE access, maybe it could go through a custom ABI?
 - string.h: just around 8 functions required
 - math.h: just around 8 functions required
 - others: 1-2 functions required for some other headers

Added SUPPORT_TRACELOG_DEBUG config

This could be required on texture packing ;)

- Renamed GetGlyphIndex() parameter
 - Review DrawTextEx() implementation
 - Review DrawTextRecEx() implementation