Implements simple boolean flag that converges towards being enabled.

The CvRDT starts with the value "off", and has a single operation, "enable", which changes the value to "on", where it stays forever.
Implements simple boolean flag that converges towards being disabled.

The CvRDT starts with the value "on", and has a single operation, "disable", which changes the value to "of", where it stays forever.
WIP OE Flag
The Swiftest of Checks
Add OD-Flag and rename to OE-Flag