Supports redmine_category_tree plugin. refs #70

Tested with the plugin version 0.0.5.
Fixes cell format like Integer, Float. refs #69, #25

Reverts cf22beb.
Changes travis env for lastest Redmine version.
Fixes routes config which has explicit method. refs #78
Avoids build of Redmine master. refs #78
Add missing russian translations.
Merge pull request #79 from Le6ow5k1/add-missing-russian-translations

Add missing russian translations.
Fixes query name of relations. refs #77
Adds closed format option. refs #76
Fixes relations exporting. refs #77
Fixes to use timezone of log in user. refs #75
Merge remote-tracking branch 'base/features' into features