Feature/counter_columns: Added counter columns and operators for increme...

...nt/decrement.

- Added ```com.newzly.phantom.column.CounterColumn```.
- Added ```increment(), increment(value), decrement(), decrement(value)``` methods for ```CounterColumn```.
- Added tests for ```CounterColumn``` in ```com.newzly.phantom.dsl.specialized.CounterColumnsTest```.
- Bumped version to 0.2.4.
- Published to internal repository.