test auth during reco auth

[CampGareth]

reco auth will now make a call to /user before saving the provided token to disk. If that call fails the token is invalid and the user is notified.

[CampGareth]

This is [WIP] because the error messages around failed auth aren't that helpful at the moment, e.g.

$ reco auth gh_00000000_foobar

Error: authentication failed. Run 'reco auth' to authenticate

[CampGareth]

Messages are now:

$ reco auth super-invalid-token

Error: The token is invalid

$ reco auth close-to-valid-token

Error: Authentication failed. The provided token is invalid

$ reco auth valid-token

2018-01-05 11:54:42| Authentication successful

[CampGareth]

reco auth should test auth

[CampGareth]

Reco v0.4.0

[CampGareth]

Reco v0.4.0