Remove workaround for browser that do not support crypto

[crazyscientist]

In the depths of the code I found a feature from 2011 to allow old browsers, which were not capable of the required cryptographic methods, the use of Helios:

1. Browser sends unencrypted ballots to the server (for encryption).
2. Server returns encrypted ballot to browser.
3. Browser sends encrypted ballot to the server (for casting).

This workaround seems to be needed only for browser versions which were released prior to the year 2012.

Maybe it would be a good time to remove it?