Added SMILESDictField

Also created SubForm class for use in internal form classes
Add type conversion into the client

Client now strips out the 'tables' definitions and performs type
conversions on row and column keys
Fix CSRF handling in API calls

The client no longer causes bad requests on the server (CSRF snafu after
switching to flask-wtf). Also added SMILESDictField conversion to forms
module and fixed min_count reference in test tool