Fixes #208.

Adds Defaults property 'ignoredChanges' which is an array of strings or regexes. Ties in with sync_methods/changes to pass into diffObjectFromOldObject method. If the compare property matches against the list of ignoredChanges, this property will not be considered in the diff.
Merge pull request #224 from Medycation/master

Fixes #208.
Stable Version 1.2.0.