Update client_side_validations-simple_form.gemspec

Bumped to 2.1.0
Update client_side_validations-simple_form.gemspec
Update client_side_validations-simple_form.gemspec
make it work with SimpleForm 3.0 and Rails 4.0

should work in coordination with https://github.com/sdesbure/client_side_validations/tree/fix_form_for_in_rails4
make it work with SimpleForm 3.0 and Rails 4.0 (part 2)

Forgot a self...
Merge branch 'master' of https://github.com/sdesbure/client_side_validations-simple_form

Conflicts:
	client_side_validations-simple_form.gemspec