detect when used as a globally installed module; error on compile/clean verbs

[ofrobots]

fix and check can be used from a globally installed gts, but not check and clean.

[ofrobots]

Actually, use of check from a globally installed gts can be problematic. We do not depend upon typescript which means that unless the user has typescript also globally installed, we will not be able to instantiate tslint's API.

Perhaps the solution is for the global gts to try and locate the local gts and exec that, similar to how gulp does it.

Secondly, we should probably provide a better error message when check fails before typescript is missing.

[ofrobots]

Probably the only verb that makes sense from a non-local installed gts is init.
For all other verbs, we should exec the locally installed copy.

[JustinBeckwith]

With the move to eslint I believe this actually works now!