fixed the bug that the number of total documents wasn't updated

when deleting a document and modified the test.
implemented a form-validation for text-inputs, now

prohibiting the user to save custom AQl queries containing special html
characters.
Merge branch 'devel' of https://github.com/triAGENS/ArangoDB into devel
Merge branch 'devel' of https://github.com/triAGENS/ArangoDB into devel