Delete ColumnConfig. The DataStores and Tables just define a Column Spec
and the Extractors and and Populators for the Columns are only
available if they extend Generic Field Based Extractor / Populators
SmsDataStore now uses generic field based extractor
Close Cursor is finally clause for DataStore
Merge pull request #37 from sarality/datastore

Delete ColumnConfig and update SmsDataStore to reflect the same. SmsData Store also uses Generic Field Based Extractor now