Rewrote string_sanitize_url() to use a simpler and more robust algorithm.
All tests in tests/test_string_sanitize_url.php now pass as expected.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@5714 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9