NoValueSnakStore now takes a tableName rather then tableDefinition

Change-Id: Ifb86c66b31149e47fa0a03500c03eaedf4cd0276
Added SnakRow->getInternalSnakType

Change-Id: I1dcd874d2406ffca29e25c3f6f2c9f5b2762f33b
Implemented SnakRow->getInternalSnakType and added tests for SnakRow getters

Change-Id: If5f10ed91406cc57687f9560e8e1557f43ab615e
Split SnakRow into ValueSnakRow and ValuelessSnakRow

Change-Id: I1deecc586bedb267512752021c9f4be66788e602
Merge SomeValueSnakStore and NoValueSnakStore as ValuelessSnakStore

Change-Id: I754bed32d74cc1e96a21740a378b21a9204c62d8