Tags case sensitivity

[Thorium]

Usually humans are searching case-insensitive style, e.g. if I search for Fibonacci sequence I actually don't care if the solution is named as the Fibonacci (correctly upper case, named after the mathematician), or is it so common term in information technology, like internet, that it could be written in lower case.

This is effecting three places:

• The tag cloud: http://fssnip.net/tags/
• The keyword search in all pages, the dark lila colour
• When adding a snippet and selecting tags

My suggestion would be converting all the tags in lower case, just to break the FXCop rule #CA1308

[Thorium]

Actually the problem is just search and http://fssnip.net/tags/ pages. I'll try to fix ans make a PR.