Add link to jetbrains

[mikaelkaron]

Since we get an open source license from them we should add a link. Snipped this from the renewal mail:

If you feel that WebStorm has helped you a great deal, we’d be grateful if you could consider a possibility to mention JetBrains’ support for TroopJS by placing a WebStorm banner at the project web-site or mentioning JetBrains support in any other appropriate way. Please, follow the link if you wish to see the banner constructor: http://www.jetbrains.com/webstorm/documentation/linklogos.jsp