Added font-related funcitons and structs

|SOURCE|
[Font]
* GLYPH struct holds a glyph, which represents a character on screen
* FONT uses a combination of an IMAGE and a GLYPH to represent a series of
  printable characters
* AddGlyph is used to append a GLPYH to the end of a glyph set
* Create takes an IMAGE and GLYPH to store in a FONT
* Destroy simply frees the memory used by the FONT
T#