Merge pull request #54 from rromanchuk/update-afnetworking

Update afnetworking
podfile.lock++
version sync'd to AFNetworking
gemfile++
use a mutable JSON container, fixes #55
mutable container tests, + webstub
switch parameters to nil by default

otherwise, your URLs will get an empty query parameter by default
Merge branch 'master' of github.com:usepropeller/afmotion