ticket:199 rename run_type to library_type everywhere
ticket:200 sample code must be always a string
ticket:199 merged master, fixed conflicts
Merge branch 't199_rename_runtype_to_librarytype'
ticket:199 fixed test_applied_filters
ticket:200 merged master, fixed conflicts
Merge branch 't200_filter_error_when_partially_set_from_url'
ticket:200 commit for buldbot
ticket:205 edited documentation for celery
ticket:205 extende howitworks.rst, added documentation for tasks used and caching
Merge branch 't205_cghub_browser_celery_tasks_documentation'