Both the TFSAlertDSL: packages contain the bulk of the code up not the actual DSL.
The DSL implementation is supplied as a separate assembly TfsEventsProcessor.DSL.Dll ; you can create your own DSL as you want, but the provided one supports all the features of the scripts document on this site. The location you should place this, and any other DSL DLLs, is defined in web.config file.
Fixes in 184.108.40.206 No changes in production code, fixes issues with running unit tests and MEF
Now recommended that you now place any DSL DLLs in their own folder as opposed to dropping them in the bin folder
Built against TFS 2015 API in VS 2015
You may also need the CreateEventSource command line tool if you intend to log to the Windows event log https://tfsalertsdsl.codeplex.com/releases/view/126004