Restored PHP 5.3 functionality.  Issue #68.
Fixing validation events and verification of relational data

! Validation events were missing their own static methods
! afterValidate wasn't being called if validation fails
! poor renaming of variables in relational data method caused some arguments to not be recognized
Correctly throwing exception on validation failure only
Merge pull request #72 from mdwheele/restore-5.3-functionality

Restored PHP 5.3 functionality.  Issue #68.
Including presence verifier for standalone usage
Allowing for personalization of error messages used by InvalidModelException
Fixing belongsTo and morphTo, that depended on caller functions (and the call stack changed with  `Ardent::$relationsData`)
Allowing for the query builder to inherit the model's throwOnFind property, thus enabling multi-level queries to throw exceptions as well (such as `User::with('relation')->first()`).
Restoring `save()` compatibility with original method signature
Adding doc about usage of Ardent outside of Laravel

The feature was finalized in commit ff41aae, but never documented.
This addition closes #60.
Executed the function within the closure.
Merge pull request #73 from aeolu/bug/hooks-are-not-called-correctly

Hook methods are now called in a closure, making them instance methods.
Including information on the new model hooks. closes #66
Small improvements on code style to follow the project style guide
Further cleaning of code examples
Including documentation about `Ardent::$relationsData`
Fixing wrong variable in sample code. Closes #75
Including new author, issues link and AR keywords
Adding doc about custom purge rules. Closes #81
Adding doc on how to auto hydrate fields when updating a record. Based on #78, closes #77