changes in response to discussion of issue #31
added log statement
only test on startup if plugin is enabled
updated Airbrake plugin version and enabled in dev and prod for DE
reverted accidental change to version number
changes in response to bostanio's first comment here: https://github.com/cavneb/airbrake-grails/pull/32
pull request 32

https://github.com/domurtag/airbrake-grails/commit/6a0d1552fc71c5225ad9c4588a5069bfc1d7e4a4#commitcomment-3139362
Merge pull request #32 from domurtag/master

Support enabling/disabling Airbrake notifications while the  plugin is running.