Added Tycho Build for this plugin

Hello,

I´ve added the necessary projects in order to make a maven tycho build and created a feature project, which is used for the p2 update-site.

I have already deployed an updatesite at http://home.arcor.de/scholzsimon/eclipse/p2

![languagetool_p2_updatesite](https://cloud.githubusercontent.com/assets/7559962/2976439/b8e4282e-dba0-11e3-9560-660be14338f8.PNG)

For further information see my Email.

Best regards,

Simon