Extracted common field configuration in default field generator tests
Removed redundant property setters in IFieldConfiguration
Changed null field configurations in tests to use default so an overload can be added
Renaming fields in tests for consistency
Introduced readonly field configuration and split out the field generator
handlers so they handle mutating the configuration and generating the HTML
separately
Ensured the form template uses readonly field configurations
Merge pull request #15 from MRCollective/friendsdontletfriendsrestoreaftercommit

Ensuring FieldConfiguration is immutable past the point it should be modified