Fixes #41
Merge pull request #42 from unixpickle/fix-slider

Update sliders to fix #41. The default sliders should not be used in custom apps and are meant as examples to show how the color picker could be used.
updated places which used contexts
Merge pull request #43 from unixpickle/unified-contexts

Swap custom context function for `CGContextCreator`.
removed sliders from README
Merge pull request #44 from unixpickle/fix-slider

Remove sliders from README
fixed up indentation
standardized pointer syntax
standardized method+function syntax
added contributing section to README
standardized RSSelectionView
cleaned up RSGenerateOperation
demo look less bad on iOS 7
updated to be state-based
state is now based off unit-circle coordinates
more consistent metrics
proper implementation of selection property
do business in layoutSubviews
woops
responds to setFrame: correctly!