Added keystate, test and implementation for click
removed magic string
Added event NewWindowOpened, to allow a client to access new windows easier
added new file KeyStateOption.cs to Mono solution
found another file that was not part of the Mono project: NeighbourSelector.cs. This caused the CSS selector + operator not to work in Mono builds
Merge pull request #85 from Teun/control-keys

Control-click -> new window