Btest

* Release 0.68.

* Release 0.67.

* Bug fix to apply TEST-REQUIRES to tests duplicated with TEST-START-NEXT.
(Robin Sommer, Corelight)

* Release 0.65.

* Change --retries option to not increment test name on retries.
(Jon Siwek, Corelight)

* Fix retrying tests that use additional files. (Jon Siwek,
Corelight)

* Add support for minimum BTest version requirement in the config
file. If an entry called "MinVersion" is present in the "btest"
section, it spells out a minimum version that BTest must have in
order to run. If that condition isn't fulfilled, we exit with
error code 1 and a corresponding error message on stderr.
(Christian Kreibich, Corelight)

* GH-29: Add new options -F/--abort-on-failure that will abort once
at least one test has failed. (Robin Sommer, Corelight)

* Documentation and code cleanup. (Christian Kreibich, Corelight)