Add classes to settings headers

No issue

Refs https://github.com/TryGhost/Ghost-UI/issues/91

- Adds a class to settings page headers, for cleaner CSS selectors
prevent revoking invite for already active users

closes #3563
- before attempting to revoke an invitation, get updated model info
- reload route and show warning if user info has changed
Merge pull request #3587 from PaulAdamDavis/settings-header-classes

Add classes to settings headers
Merge pull request #3593 from morficus/issue-3563

prevent revoking invite for already active users
Improve spam prevention

closes #3544
- limit forgotten password requests to five requests per IP per hour
for different email addresses
- limit forgotten password requests to five requests per email address
- limit signin requests to ten failed requests per IP per hour
- removed special treatment for tests
Cleaning up old html files
Fix embedded code being removed

no issue
- changed order of escaping
Merge pull request #3595 from sebgie/issue#3544

Improve spam prevention
Merge pull request #3598 from sebgie/fix-embedded-code

Fix embedded code being removed