Fixes client side bio character counter.

closes #1432
Change fallback from address to webmaster@[blog.url]

This change is needed because the previous default of the user's email
address is too often mismatched against the site domain, triggering spam filters.

Fixes #2145
- added `fromAddress()` to GhostMailer to handle this logic
- added unit tests to `mail_spec.js`
Renamed client-side admin url helper

fixes #2254

- includes test
/ghost/reset/* should not redirect to signin

fixes #2257
Cleanup naming & order in admin controller

no issue

 There seemed to be no convention or order to the functions in the admin controller, so I have:
 - organised them
 - reordered them
 - added a small doc-block
 - reordered some routes
 - updated tests accordingly
ReadMe Improvements

SEMANTICS ALL UP IN THIS WHAT
Merge pull request #2258 from ErisDS/admin-ctrl-cleanup

Cleanup naming & order in admin controller
Implements the #has Block helper

closes #2115
- Added new #has block helper
- Added several tests for #has helper
Merge pull request #2153 from halfdan/2115-has-block-helper
Merge pull request #2252 from jondavidjohn/from-address-default

Change fallback from address to webmaster@[blog.url]
Merge pull request #2246 from knunery/issue#1432

Fixes client side bio character counter.