Upgrade redmine versions
Add rake dist task to build targz
Merge Rakefile, spec_helper and runner utils from master
Check for issue_id plugin method
Update locales

* Thanks to all translators on Transifex
Update CHANGELOG
Release 2.4.0

* Add integration patch for ISSUE-ID plugin. The dashboard will now show
  the modified issue IDs if the plugin is installed too.
* Update locales including the new Polish translation. Thanks to all
  translators!
Merge tag 'v2.4.0' into debian