Get lang from instruction when provided.

If instruction list includes a tag with _LANG_MT, then lang is set to MT
and no call is made to the DetectLanguage API.
Use publishable (as well as listable) scope for notes shown in tags pages.
Revise VCR usage in tests
Tidy up
Update gems
Refactor Note

Put anything that handles evernote requests into EvernoteRequest.
Update gems
Improve formatting of text
Improve styling