Only validating models on commit when { validate: true } is passed

Adhering to the behavior specified in the documentation
Build
Updating changelog
Using Backbone 1.1.0 in tests. Noting compatibility
add browser entry in package.json
gist.github.com/defunctzombie/4339901
use window || global || this instead of assuming that this is always global
exports Form for commonJS
build
Update version
Update README.md
Merge branch 'master' of github.com:powmedia/backbone-forms

Conflicts:
	distribution.amd/backbone-forms.min.js
	distribution/backbone-forms.min.js