First version of the api search

- requires the auth key of a user and the user has to have auth key permission

- user can specify what should be returned (event / attribute) - currently only event is implemented

- user can specify 4 filters (value, type, category, org)

- all these fields can have several values separated by &&

- Values can be negated by putting "!" infront of them
First round of implementations for the new API searches

- users can search RESTfully for attributes based on various filtering mechanisms and get either an event that includes the located attribute(s) or just an array of attributes returned.

- users can also request all attributes of a (or several) types and get them returned as an XML
Security fix and new download attachment feature

- users can now download attachments using the APIkey

- security issue fixed where a user could download attachments that he/she can't even see by navigating to attributes/download/<attribute_id>
First release of the new API features
 Merge branch 'feature/searchapi' into develop