CAL-414: Calendar crashes with username of illegal XML name

Problem analysis:
* Username is used for personal calendar.
  When this name doesn't follow ISO9075 encoding of XML names, it breaks XPath queries.

Fix description:
* Escape personal calendar path.
Crowdin injection w16 (from 20140412 to 20140416)
Merge branch 'stable/4.0.x' into feature/4.0.x-translation