To Add Other ERC20 Tokens:

Check to be certain that the ERC20 token is correct at
CoinMarketCap.com (it will show ERC20 token and the address 
should be same style as an ETH address).

Open index.html in an editor and go to approximately line 79
copy and paste the Ethereum line and then change the 
name to the correct name of the token you are adding.
And also copy and paste the section approximately at 325 and change the name.

Now open js/brainwallet.js in the same editor and jump to approximately 
line/section 508 and copy and paste the Ethereum section and change 
the token name to your new ERC20 token.

Add the icon as a 64x64 png file to the Icons folder, grab the icon from
CoinMarketCap.com

Save your new index.html file and test!

-----------------

To change the 20 minute timer:

Open js/app.js with an editor and change line 19 to the desired time in seconds,
and open index.html with an editor and change line 15 to the same.