Extract xcore cli implemenation.

We want to house the implemenation of each function for the cli
tool into it's own file. For example build-client should be in
it's own .js as well as test, etc.
Merge in Chall's xcore cli fixes
Reconciled @chall client code. Stubbed usage.
Able to wipe views with build script.
extension scaffolding script

you can generate a new extension when you call xcore new extension <name>, an extension of the desired name is generated in the lib/extensions folder, along with other essential files and folders