Added r16b01 as a test target.
Added ablity to verify mfa defined types on from_json
integer min/max type implemented.
Added limited length string type.
Added test to handle type of list of custom types.
Added test for going to json w/ custom types.
Added field_types function to generated code.

this means users of the record can now dow things like get the list
of fields and determine how a particular value is validated.
bumped version to 2.0
Renamed rec2json_compile to r2j_compile

Less typing makes me happy
All tests pass after big refactor.