Add Unicode tests, fix whitespace, fix docs

Added Unicode tests (and fixed few bugs), changed whitespace script to
proccess markdown files, added new guide to showcase how to work with
Unicode.

doc/Features.md

@@ -11,15 +11,15 @@ Currently implemented features:
 - Intersection calculation (ray, boxes, segments, lines, planes, triangles)
 - Unit testing library (for internal usage)
 - Command-line interface utilities
+- Thread support (thread, mutex, cv, atomics, etc.)
+- Unicode support functions (BMP, UTF-8, UTF-16, UTF-32)
+- String conversion functions from/to numbers
 
 ## Planned features
 
 Currently planned features:
-
-- Thread support (thread, mutex, cv, atomics, etc.)
 - Image loading/processing/saving support
 - Polygon rasterization (possibly canvas)
-- UTF8 string support (BMP handling)
 - Font rendering
 - GUI (Windows GUI, X11)
 - Deflate/Inflate implementation