Integrate the various linters into travis.
Integrate the various linters into travis.

From a local repo, you can type "make lint" to run the same
things Travis would run.

A number of linters are currently turned off due to the config
problems in the denyChecker package. Once these problems are
fixed, we can enable the full breath of linters.

This also fixes a number of lint errors.


Former-commit-id: 78ba896198870b6e3e51a0ec431471ebfb9d5a26
istio/pkg,istio/pkg,istio/pkg,istio/pkg,istio/pkg