Merge pull request #15 from colinta/master

Adds `from_{left,right,top,bottom}` methods, and some fixes
add MIT license. fixes #14
Merge pull request #17 from colinta/master

(fix) allows ':margin' as option in above, below, before, beside
added #to_ary to cg_point this method allow us to do parallel assignment of x and y
added #to_ary to CGSize this method allow us to do parallel assignment of #width and #height
added #to_ary to CGRect this method allow us to do parallel assignment of #origin and #size
version bump
adds 'to_ns_value' methods and ensures to_ary is available
apply options, don't merge
adds CGRect#integral
whitespace
0.15.0