Added a Activities tab to Project Settings

Added a Activities tab to Project Settings

* Changed Project#activities to allow getting inactive Activities also:
  * Changed the Enumeration#all named_scope to exclude project specific Activities
  * Changed the Project has_many time_entry_activities to include all by default
    and provided an #active method to filter them to active ones only
  * Split Project#activities to two methods and gave it a parameter that is used
    to determine if inactive activities are included (default is no)
* Added a reset button to delete all project specific activities.
* Added ProjectsController#reset_activities to remove the project
  specific activities
* Added a HTTP DELETE route for reset_activities
* Changed the permissions for managing project activities to have access to the
  ProjectsController#reset_activities action
* Added a way to bulk save Project specific Activities in ProjectsController
  * #save_activities will save all the changed activities, including update the
    existing records
  * Added helper methods to the controller which will be refactored later
  * Allow the same TimeEntryActivity names on different projects

  #4077

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2949 e93f8b46-1217-0410-a6f0-8f06a7374b81