Implement HTTPS support for retrieving node API.
Refactor SSLAdapter to use arbitrary SSL version.
Fixes #585. Check node API certificate if using HTTPS.
Handle SSL error on certificate verification.

* Extend State model to store ssl_verification.
* Warn user if state retrieval can be from a untrusted source.
Parse node response when cames from an untrusted source.
Show SSL cert verified on UI and controller API. refs #585
Extend state controller API to include data and metadata. refs #460.
Cosmetics. Improve verified tooltip and help text. refs #585 note 10.
Extend state ctl API. refs #460.

* POST request refresh state data.
* Added last_try_on field.
Merge branch 'bug585'