Patent Assignment Data Restructure

In order to restructure the current patent dataset, the data requires rigorous cleaning. The primary areas for improvement are:

1. Clean ptoassignment table to unique keys.

2. Clean ptoproperties to remove nonutility patents (including patent numbers, application numbers, something else that we haven't matched yet).

3. Clean ptoassignee to extract address components and clean it up.

4. Check all patent numbers accounted for in ptoassignee_currentusa

5. Correspondence address clean up.

6. Transform structure.