Updated README

Updated README with version 0.0.2 changes.
Additional row+column parent pages select

- Added ability to select row and column parent pages via a Page Field.
The respective child pages would create the matrix table's rows and
columns.
- This change allows reusability of one matrix field across
pages/templates with each page able to have its unique matrix table
(i.e. made up of different rows/columns.
- Code cleanup
- Bumped version to 0.0.2