Refactor MandrillEmailer to make it easy to send other emails with installer links.

This was actually developed against master and may not work until I merge master.
Merge branch 'master' into update-emails

Conflicts:
	src/main/java/org/lantern/FallbackProxyLauncher.java
	src/main/java/org/lantern/SendInviteTask.java
	src/main/webapp/WEB-INF/appengine-web.xml
	src/main/webapp/WEB-INF/web.xml
Fix one merge artifact, email all users.
First shot at transifexable update notification email template.

This is just a modification of the invite-notification.tmpl to
slightly change the text and add a *|VERSION|* mergeVar.

I'm not sure I was supposed to put the English version as
preliminary text in the other languages, but generate_emails.py
would crash on me if the entries were missing in the language
json files.
Improve error checking and reporting in admin/index.jsp.
Make Dao.getAllUsers return the query itself.

Here's hoping that the iterable is more memory friendly than reading
it into a list.
Little capitalization fix.
Avoid possible NullPointerException.
Merge pull request #49 from getlantern/update-emails

Update emails