update readme to include ttf info
another modification to make dealing with colors easier.
free memory as needed
Merge branch 'master' of https://github.com/jackyb/go-sdl2

Conflicts:
	README.md
fix relative import paths so go get doesnt complain
implement more attributes of fonts and add some constants
Merge pull request #18 from whyrusleeping/master

Some more functions implemented and a few fixes