Adds Access Control for object based rights.
First draft to implement role based rights (group based rights)
Adds Role Based Access Control (group_rights), including test
Improved filter
First draft for ACL in the webapp. Needs searching.
Change way how rights are saved. It uses subdocuments with booleans, instead of an integer. Bitwise operators in MongoDb are not extensive and need JS (which slows it down). The communication between client and server still uses the integer versions.
Adds a search index and a search resources. The engine is rather simple. It does use weighted keywords, based on weights given to specific fields. When searching, the part of the keywords are considered as first part of a word. /^[keyword]/
Added search support to existing resources.
Merge branch 'feature-search' into feature-acl, and updated the access_control and the test to the new hashed rights (instead of integer)

* feature-search:
  Added search support to existing resources.
  Adds a search index and a search resources. The engine is rather simple. It does use weighted keywords, based on weights given to specific fields. When searching, the part of the keywords are considered as first part of a word. /^[keyword]/
  Change way how rights are saved. It uses subdocuments with booleans, instead of an integer. Bitwise operators in MongoDb are not extensive and need JS (which slows it down). The communication between client and server still uses the integer versions.
  Fixes a critical bug when opening the SelectFile dialog and a mime-type of a file is null.
  New version
Some minor fixes
Removes sample import from users resource.
Merge branch 'feature-search' into feature-acl

* feature-search:
  Removes sample import from users resource.
Added API maintenance entry-point, with the first maintenance task: reindex_search. Also adds support for reindex_search all resources.
Improves use of api_url in objects and adds it to the search index.
Adds String.truncate and default description support in for search_indexes.
Adds support for filtering categories in search_index.
Adds AutoComplete.js, including some tests and styles
Removes useless index on search_index and backwards compatibility (temporarily) for numeric rights.
Adds adding users and groups on AdvancedObjectRights dialog, using AutoComplete.js.
Fixes bug in DbObject.rights_hash_to_int, when hsh = nil.