update_with_password doesn't change encrypted password when it is invalid

closes #2130
Merge pull request #2132 from nashby/issue-2130

update_with_password doesn't change encrypted password when it is invalid
Unlock user when re-setting password and unlock strategy is :email or :both
Merge pull request #2134 from marcinb/master

unlock user after password re-set
remove useless test
Merge pull request #2137 from nashby/indifferent

remove useless test
update README

closes #2128
Fix spec failures for Mongoid 3.

This has no actual changes to Devise itself, just fixes the failing
tests when running against Mongoid 3 instead of Mongoid 2.

Mocha has been locked at 0.10.0 since 0.12.0 raises an error when trying
to set an expectation on a frozen object.

Tests were updated to work with both AR and Mongoid, some cases the XML
serialization was slightly different but both were outputting correct
and valid XML, and the id/_id field mismatch is now handled.

An active field was missing from the test models for Mongoid, and the
invalid :null => true options in field were removed.
Merge pull request #2139 from durran/mongoid-3-test-fixes

Fix spec failures for Mongoid 3.
Merge pull request #2138 from nashby/patch-1

update README
Update README.md
Update CHANGELOG
Update Gemfile.rails-3.1.x.
Update Travis CI configuration:

* `DEVISE_ORM=mongoid` is part of the build matrix, except
  for 1.8.7 and REE rubies;
* `language` key added (Thanks to travis-lint).
Remove 1.9.2 + Mongoid from the build matrix.

http://mongoid.org/en/mongoid/docs/tips.html#ruby
Show invalid confirmation token message

fixes #2143

Attribute confirmation token is not present in the simple_form template,
therefore not being displayed by #error_notification.
This fix explicitily call #full_error on :confirmation_token.
Show invalid unlock token message

Attribute unlock token is not present in the simple_form template,
therefore not being displayed by #error_notification.
This fix explicitily call #full_error on :unlock_token.
Use correct current_password in RegistrationTest of invalid confirmation

In DatabaseAuthenticatable#update_with_password, password is now deleted if
the current_password is invalid. dm-validations will not check the
confirmation in that case, so this test was failing in dm-devise.
Merge pull request #2144 from jm81/master

Use correct current_password in RegistrationTest of invalid confirmation
Support alternate sign in error message when email record does not exist

By default, the nonexistent error is still identical to the :invalid
message, and must be customized by the developer to implement.