Improve markup and style sheets

* Fixes inconsistency with input wrapper classes.
* Improves markup for secondary links. Adds sign in link to sign up form
  for better navigation.

https://github.com/thoughtbot/clearance/pull/252
Add "#clearance" wrapper to markup
Prepare Clearance for Rails 4

* Change routes to use `get` instead of `match`.
* Don't allow multiline strings for email format.
* Rails 4 issues an exception when validates_format_of encounters regex
  that uses ^ and $ rather than /A and /Z. See this pull request:
  https://github.com/rails/rails/pull/6569
* `sign_out` should use DELETE, not GET.
* Remove irrelevant spec for testing regex.
* Test against latest security-patched Rails versions.
Persis BCrypt password during SHA1 migration

A full description of the issue this resolves is here:

https://github.com/thoughtbot/clearance/issues/236
Improve readability of locales
Improve UX of password reset

As reported on:

https://github.com/thoughtbot/clearance/issues/250

By default, the text on the password reset page read:

> We will email you a link to reset your password.

This implies that the system is already in the process of sending an
email,
and that no further action is required by the user. We have had multiple
users of our application fail to complete the password reset flow
because of
this confusion.

Here's how these users got stuck:

* Visit the login page.
* Enter their email address and an incorrect password.
* The application denies login with "Bad email or password" error.
* User gives up and clicks "Forgot password?" link.
* Reset password page loads with the text "We will email you a link to
 reset your password.". User thinks they are done. (After all, they
 already provided their email address on the login page.)
* User never completes the reset password form. Telephones support
 complaining their password is not being reset.

Our fix was to change the password reset text to:

> To be emailed a link to reset your password, please enter your email
> address.
Add psych as development dependency

* Eliminates warnings and errors when psych is installed
Add Clearance::BackDoor for signing in quickly in tests

http://robots.thoughtbot.com/post/37907699673/faster-tests
Make PasswordsController#create case-insensitive

* Centralize email normalization logic in `User.normalize_email`.
* Implement `User.find_by_normalized_email`.
Removes duplicated sign up and forgot password links
Move password email delivery to private method

* The password email delivery can now be overridden
Include certain helpers only for controller specs

Travis CI was failing because of the conflict between the `sign_out` method
meant for integration tests and the `sign_out` method used for controller specs.

Example failure: https://travis-ci.org/thoughtbot/clearance/jobs/4730477
Bump up gemfile versions in travis-ci config
Fix broken links in README

* GitHub changed how links work in Markdown files:
  https://github.com/blog/1395-relative-links-in-markup-files
* Link to i18n translations in README so it is clear what the key
  hierarchy is that can be overriden.
* Break long lines after 80 characters.
* Order lists alphabetically.
Rename i18n keys for password email

* Take off _paragraph prefix because text does not contian <p> tags
* Change password text copy to be more clear.
* Sort i18n keys alphabetically.
* Resolves #248
Replace email regex with EmailValidator gem

* Use Rails 3 `validates` method.
* Use Ruby 1.9 hash syntax.
Fix error in Blowfish, SHA1 password strategies

* Bug report:
  https://github.com/thoughtbot/clearance/issues/222
* Remove duplication in spec suite.
* Extract `fake_model_with_password_strategy` spec helper method.
Bump bersion to 1.0.0-rc5
Use env[:clearance] instead of env[:session]
Update documentation

Use more recent gem version that includes the integration tests
generator.