Added new test case for EZP21906 - Search API returns wrong number of total objects with content having multiple locations
Throw exception on invalid header name
Set content type header correctly
Added mandatory version field to schema
Fixed string
Escape slashes in subtree query

TODO: Provide sane general escaping in Solr strings?
Try to configure Travis to run tests with different Solr versions
Fixed build matrix in Travis config
EZP-22045: Implemented base login in Symfony security context
EZP-22045: Inject current user in legacy kernel