add trac issue tracker support

[stevecrozz-]

I've just wrapped up a first try at integrating trac as an issue tracker via the Trac XmlRpc Plugin. I've tested this with trac 0.12.3 and it's looking pretty good.

[coveralls]

Coverage increased (+0.22%) when pulling 3417778 on stevecrozz:experimental_trac_support into ca25b8b on errbit:master.

[shingara]

Thanks to do this Pull Request but I am in complete part of extract all issue_tracker to separate gem. So I don't merge it before this work. After you can create a gem to allow this issue_tracker.

[stevecrozz]

shingara: This is good to know. Do you have an idea of when you will make this change? Is there a feature branch I can look at to see what's coming?

[shingara]

All information is now on a pull request #612

[niQo]

I am very interested in this plugin. Tell me if I can help.

[stevecrozz]

I have re-implemented my plugin as a gem on top of the new issue tracker paradigm @shingara plans to introduce with: #612

My new gem is errbit_trac_plugin https://github.com/brandedcrate/errbit_trac_plugin (https://rubygems.org/gems/errbit_trac_plugin). This pull request no longer applies in its current form, but it might still be needed if errbit_trac_plugin should be included in errbit's Gemfile. After PR #612 is merged, I can update this PR to include only the Gemfile change.