Bumping version to '2.1.6'.

Removed some doubles.

Bumping version to 2.1.5

Bumping version to "2.1.4"

Bumping version to "2.1.4 pl1"

Bumping version to '2.1.4 rc1'.

Bumping version to "2.1.3" final

Bumping version to "2.1.3 pl1"

Merge branch 'release/2.1' of github.com:bolt/bolt into release/2.1

Tagging v2.1.2