[JENKINS-22597] Error 404 when trying to access language details for "C/C++ Header"

- Helper method HtmlUtil.urlEncode() defined.
- getUrlName() method added to Folder, Language and Module classes and used for all URLs in HTML links.
- URL decoding is done out of the box in SloccountResult.get*Result() methods.
Merge pull request #41 from mixalturek/master

[JENKINS-22597] Error 404 when trying to access language details for "C/...