Support observable params objects

Support observable params object i.e. for "min", "max" to be observable.

This change just calls unwrapObservable before invoking the validator
functions.

# Changed test-runner.htm: confirmPassword needs to be required to fire
error as both, password and confirmPassword, are initially undefined.
Minor test naming fixes
Merge pull request #363 from warappa/master

Support for params to be an observable

Should also fix #138