update multi_xml version to most recent one, since previous versions were unsafe like rails.

see: https://github.com/sferik/multi_xml/pull/34
Merge pull request #356 from universal/update_multi_xml

update multi_xml version to most recent one
Get turbo-sprockets-rails3 back
To substitute mongodb by mongodb-10gen.
Merge pull request #357 from khustochka/get-back-turbo-sprockets

Get turbo-sprockets-rails3 back
Merge pull request #359 from danielbayerlein/fix-readme-mistake

[README] To substitute mongodb by mongodb-10gen. [ci skip]
update gitlab gem