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
Adds test stubs for query tests
Fleshes out basic query tests (failing)
Adds custom exceptions for .find_one()
.find() now accepts query lists of zero length
Adds simple tests for queries