v0.4    2018-07-11

    * Bugfix #1: Mark mutators as is rw. (HT: @AlexDaniel)

v0.3    2018-03-15

    * Second attempt to fix type problems in assigning $!token from the
      environment.

v0.2    2018-03-15

    * Fix a small type problem that breaks tests in certain cases.

v0.1    2018-03-11

    * Initial release.
