Merge pull request #3 from trystan/master

simplify api and change default foreground color
Merge pull request #4 from trystan/master

Improve performance
Merge pull request #5 from trystan/master

Allow different fonts.
remove trace
fix for writeCenter not using correct colors
use nullforegroundcolor and nullbackgroundcolor when null is passed as a fbcolor or bgcolor
add documentation
rename deafult and null foreground and background color properties