Refactored Skinny ORM, added SkinnyNoId(CRUD)Mapper

 - SkinnyNoIdMapper, SkinnyNoIdCRUDMapper are newly added
 - Much refactored internal duplicated code
 - SkinnyTable is marked as deprecated
 - SkinnyJoinTableWithId is marked as deprecated
Merge pull request #128 from skinny-framework/feature/non-relational-table

Refactored Skinny ORM, added SkinnyNoId(CRUD)Mapper