CallbackCommentMetaStore now has some very dubious but effective code for retrying when we fail to read or write to the brain due to IOException.

Bumped version #
We now notify, color based on new/update comment and change the from to be "bitbucket" for bitbucket commits that are output by the bitbucket script.
Implemented support in script for:

* Listing commits which have been approved (we store results so we don't show the same user/commit approval repeatedly).
* Listing unapproved commits
* Listing total commits approved by each user.

The duration for each of these commands is controlled by the INI settings:

MMBOT_BITBUCKET_DAYSFORCOMMENTS (defaults to 14 days)
MMBOT_BITBUCKET_DAYSFORAPPROVALS (defaults to 14 days)
MMBOT_BITBUCKET_DAYSFORAWAITINGAPPROVALS (deaults to 7 days)
MMBOT_BITBUCKET_DAYSFORAPPROVALSUMMARY (defaults to 30 days)