Validate parameter keys.  Only allow parameters that are defined in the api method definition if the validate_keys option is set to true for the config.  If unknown params are passed in an UnknownParam exception will be raised.
avoid calling to_sym on user input, check if empty instead of unless > 0
Merge pull request #122 from dfharmon/master

Validation of submitted parameter keys
Merge branch 'master' into allow-validations-in-before_filter

Conflicts:
	spec/controllers/users_controller_spec.rb