Converted the validators to classes
Renaming of convention

Anything validatable must respond to 'validate()' and return a promise.
If the validation passes, the promise resolves. If it fails, the promise
is rejected.

In the property validators, the Base.validate() method expects the
property validator to respond to 'call()' for running the actual
validation. Base.validate() will handling the promise.
Extracted conditional validator tests into its own file
Validators rebuilt on each validations run
Support composite validations
Updated to rc6
Error messages are live updated
Composite Validator support updated

* Removed state machine support
* Custom validator
* Property validator
* Property array validator
Simplified validator resolution
Updated README
Updated README
Added isInvalid boolean
Fixed syntax error in example in the readme.
Cover validators on undefined properties

Properties that should be validatable but are not yet defined will be
oberved until they are defined. It is expected that the value will be
validatable.

Also added coverage for mixing validations into controllers
Updated ember dep to rc.7
fixing typo
Fixed for RC8
Uncommented test
Support shortcut syntax for numericality

Closes #19
Added support for validating length against a property on the model to the updated master branch.