WIP dump of refactoring to TypeMapper.
Merge branch 'release_0.1.0' into fetaure/field_refactor

Conflicts:
	kim/serializers.py
	kim/type_mapper.py
Removing TypeMapper and implementing Field
reverting to Type.validate
Implementing attr_name change from develop
Removed validators list attr from BaseType
imporved readability of Field name and type handling.
removing duplicate tests
Handle read_only via Field api.
Refactoring validation handling via Field api.
Set Field name and attr_name when using Serializers
removed more tests for removed features.
check if field_type is a class not a kim type.
Added docs for new Field params.
renamed attr_name to field_id.
renamed serialize_value method on Field api.
Added extra_validators hook to Field api.
Removed unused TypeMapper and old Field apis.
Removed unused Field validation functionality from Type api.
Call field.is_valid not validate from Nested.validate