Dublin core / Set keyword from thesaurus and contact from directory

## Choose keyword from thesaurus

Add capability to define keyword from any thesaurus available in the catalog in Dublin core records. Each keyword fields provide autocompletion by default on all thesaurus. A thesaurus selector is available in order to restrict autocompletion on a particular thesaurus.

![image](https://cloud.githubusercontent.com/assets/1701393/4560057/08820ff8-4ef2-11e4-8fc2-e641f37943c3.png)


## Select contact from the contact directory

Each contact fields in Dublin core (ie. dc:creator, dc:publisher, dc:contributor, dct:mediator) provide autocompletion based on the content of the contact directory. The value is set to the title of directory entry which is for a contact "organisationName (individualName)".

![image](https://cloud.githubusercontent.com/assets/1701393/4602055/9c89a916-5124-11e4-8c10-806c432bdff3.png)


## Misc

* Update to latest typeahead version which provides better configuration for the source of the autocompletion and it's easier to trigger the dropdown menu to appear. It may also helps improving #561 (see rateLimitWait & rateLimitBy in https://github.com/twitter/typeahead.js/blob/master/doc/bloodhound.md#remote)