Merge pull request #134 from wjzijderveld/issue-96--literal-namespace

Issue 96: literal namespace
Added xpath Util class with escape method
To be removed. Proof of concept of tests for hard characters
Removed htmlentities, updated Xpath::escape
Cleanup
Renamed delimiter to enclosure, removed unused var, added example to docblock
Changed escaping from backslash to quotes (works in all 3 platforms instead of 2), moved the backslash escape to seperate static method and made it simple
Moved escape call to return statement again
Simplified stuff