Major revision, added or refactored various funcs and tests

Clarified function documentation
Simplified printString(), printInt(), printFloat(), printComplex() and
printChan()
Added printInterface(), JustifyLeft() and JustifyRight()
Refactored Printf() and Sprintf() to bring their functionality inline
with fmt.Printf()
Renamed addIndent() to Indent()
Added Width()
Renamed addSpaces to JustifyLeft()
Added JustifyRight()
Refactored tests to reflect changed behavior and streamlined functions
Added additional tests for Indent(), Width(), JustifyLeft(),
JustifyRight()