Update logging

Use the more module-friendly logging style.
except clauses: use python3 syntax
[nfc] whitespace: space things out more narrowly
Update to Python 3.x
[nfc] version and date bump
Add support for desktop notifcations
Version bump
Retry more obsessively

Might handle some cases where files changed underneath Unison better.
Rework command spawning a bit

"Flat is better than nested."