jtauber/pyuca: 1.2

This adds support for Unicode 8.0.0 on Python 3.5, 9.0.0 on 3.6, and 10.0.0 on 3.7-dev.

• allkeys.txt are shipped for 8.0.0, 9.0.0, and 10.0.0 as well as the exisiting 5.2.0 and 6.3.0
• support for @implicitweights in collation element tables was added
• the implicit weight calculation code was extended not only to support @implictweights but also code point additions to the blocks in the Han Database
• from pyuca import Collator will give a Collator appropriate to the Python version (not just 2 vs 3 but 3.4 vs 3.5 vs 3.6 vs 3.7+)
• fixed some inconsistent code formatting and misspellings