Added functionality to confirm user email address.

That's the only way we can be sure the email address provided is
actually valid: if the account is confirmed.
Added account deletion.
Bugfix: marker is updated to current click location.

Even though the position of the last marker was used, every click placed
a new marker instead of updating the old one to the new location. Now a
new marker is created everytime (hmm, can I use just one marker?).
Everything else is marked for gc.
Use one marker. Reuse on subsequent clicks.

No need for creating new marker every time. Awesome!