Added a TEXT_DrawString function to draw mulitple characters

|SOURCE|
[Font]
* Added an advance and bearing for positioning the text
[Text]
* DrawCharacter draws from the point specified as the pen line
* Added an output parameter to DrawCharacter which dispenses the advance
* Added DrawString to draw a series of characters, depending on them being in
  the glyph set for the font
[Main]
* Added glyphs for printing the string: "Testing Font"
* Using TEXT_DrawString to print the test "Testing Font"