Pycomm3

Fixed minor issues with the program scope tag names containing an extra 'Program:' in the tag name

- fixed issue with program scoped tags in read/write methods
- fixed issue with parsing some custom string types inside structures
- other minor changes

data_types property added for access to struct definitions without having to loop thru tags

Minor fixes to documentation and rearranged some methods. Published to PyPI.

This release includes new methods (read/write) for the LogixDriver class. They replace the existing pycomm read_tag/read_array/read_string ( and corresponding write methods) and offer many quality of life and performance improvements over the existing methods. The intention is that these new methods will replace the existing API and the older methods will be removed in the future. These new methods leverage the tag definitions uploaded from the controller to provide many enhancements that other similar libraries don't offer. This library is still very much a work in progress, but these new methods have proven stable enough for my use case and I decided it was time to move them to the master branch. Pull requests for tests/documentation/bugfixes/enhancements/etc are always welcome.

Renamed the CLXDriver to Logix Driver, since it works with both CompactLogix and ControlLogix.
Bugfix for issue using array tags when using Symbol Segment Addressing and not Symbolic Instance Addressing.