Fixes import errors due to changes
Fixes failing tests for datetime defaults
Fixes type validators for bools and ints
move add_field to metaclass; fix bug on implicit _primary_name / _primary_type
Merge branch 'feature/fix_tests' of https://github.com/lyndsysimon/modular-odm into develop
fix remove() on foreignlist
remove _clear_caches() from __init__; this causes confusing behavior