Updating and cleaning the GUI Toolkits

- Added Xwt
- Added the new QtSharp
- Moving Qyoto and Qt4Net to Dead Toolkits as they are... well... dead
Fixed typo
Removing bad example
Better example
Fixing grammar errors
More fixes to gui pages
Merge pull request #67 from thiagoabreu/gh-pages

Updating and cleaning the GUI Toolkits
Fixed invalid link
Switch off hard_wrap for kramdown's GFM Markdown and fix the few cases where the html output would've changed
Added Travis CI