Avoid requiring files of the gem in Rakefile to avoid redefined metho…

…d warnings

1.3.3

1.3.2

Automatically run bundle install before running tests

Promoting 1.3.1.pre to 1.3.1.

Prepare a 1.3.1.pre gem to test things for the 1.3.1 release.

Prepare the 1.3.0 release.

1.2.3

Fix Concurrent::Map default_proc arguments

* Fixes #993

Prepare CHANGELOG for next version