Use client-sessions to securely store session data in cookies.

It seems client-sessions wants the cookie name to be the same as the name
of the property attached to `request` which contains the session data, so
I had to change the cookie name from `csol_state` to `session`. Hopefully
this isn't a big deal.
separated log in and sign up as per #621
changed print this page copy for sitewide consistency. fixes #619 as well.
updated no_data text. fixes #399
Merge pull request #625 from curlee/master

Various tickets
Styling for error-state password meters
Updating template field handling
Adding email validation
Fixing some validation
Making sign-up forms a bit more informative
Merge branch 'master' into auth

Conflicts:
	views/auth/signup-next-child.html
	views/auth/signup-next.html
	views/auth/signup.html
Typo
Updating LESS to include CSS changes from 489a17
Updating copy for new-learner modal

Resolves item in #621
Merge pull request #629 from andrewhayward/tweaks

Various bits and pieces
Merge pull request #627 from andrewhayward/auth

Auth updates
updating version number in package
many fixes for <13 messaging
This adds Twitter and Facebook sharing using the "Build your own Tweet button"
and Share Dialog methods, respectively. Both are javascript and iframe free;
instead you link to a specified url. For Twitter customization arguments
are sent through query parameters. Facebook requires you to put open graph
meta tags at the shared url.

Right now the user has to ensure their badge is made public before sharing.
Nothing stops you from sharing a private badge, but that link will be broken
when people try to visit it.
Removing problematic words from noun list