Merge pull request #40 from jmay/master

Make :prefix work on OSX
Merge pull request #45 from jmay/master

retire abhack.m - requires RM >= 2.8
Sorting the address book using Apple's recommended method
Merge remote-tracking branch 'madewulf/master' into sorting
protect simulator AB while specs run
sorting via OS or custom in AddrBook#people
DRY: Person#all now using same fetch-and-sort as AddrBook#people
block on auth before running specs in ios7
updated README
group#remove, group#add(multiple)