Remove data-action attribute in buttonEnabler

fixes #701 on github.

The 'Add Tree' anchor tags use a 'data-action' tag to enable the add tree mode. The button enabler removes this action in the case of disabling or redirecting, in order to prevent this behavior from leaking through.
Add google analytics and setting. Fixes #236.
Use registration form to prevent duplicate emails

Fixes #725.

We enforce this both at the database level, and here, using django
registration's ready-made form class.
Merge pull request #737 from steventlamb/bug/701/add_tree_not_redirecting

Remove data-action attribute in buttonEnabler
Fixup whitespace
Add SUPPORT_EMAIL_ADDRESS to settings

Fixes #676.

This was already wired up in some places- but it hadn't been
defined. Now it should be used everywhere where a contact/support email
is needed.
Merge pull request #740 from ahinz/fix/676/support-email

Fix/676/support email
Merge pull request #738 from ahinz/fix/236/add-google-analytics

Add google analytics and setting. Fixes #236.
Merge pull request #739 from ahinz/fix/725/duplicate-email-checking

Use registration form to prevent duplicate emails
Add name to user url for use in reverse url lookups
Merge pull request #749 from maurizi/master

Add name to user url for use in reverse url lookups