Pywrangle

- Removed walrus operator for Pre-3.8 compatability. Now Python 3.6+ compatable.

- Removed identify missing data from library -- too much overlap with the missingno library.
- Added identify_errors() function. Uses levenshtein's distance & double metaphone string matching algorithms to identify potential data entry errors in string columns.
- Refactored code into different sub libraries
- Placed documentation on ReadTheDocs.

- refactored code for clarity
- added display info to print_df_changes

- Created __init__ file for function imports
- Documentation on importing pywrangle
- Added numpy as required package.
- Changed package requirements to greater than or equal to.

- Init