Changes to event modifiers for CGEventSetFlags

This isn't the nicest of code. And not entirely sure whether its doing anything much better - but commands are being sent more reliably (apart from shift ones) (e.g. try https://gist.github.com/willwade/52ccf1455772d6597c30 ) (Apologies for the eval.. was a quick hack)
added more modifier possibilities

now added a way for more than one modifier to be possible
Merge pull request #43 from willwade/master

Event modifier code addition