Update Makefile

Bump version

Added all relevant changes since 0.86

Added release date (today) to CHANGES.TXT

Edited docs/README.TXT a bit

0.85 (2017-01-23)

0.85b (2017-01-26)

0.84 (2016-12-16)

0.83 (2016-12-13)

0.82 (2016-08-15)

0.81 (2016-06-13)

0.80 (2016-04-24)