old style multi keys

This is an older method of enabling multi-keys. It will continue to work and be supported in code, simply because I prefer it. But I am not going to document it except for the example below, nor am I going to support it in terms of questions. Sorry. Apparently it was too complex to understand, even for some smart folks I know. This tells me it was probably ill thought out and should have been obsoleted as soon as e0fe73a was pushed.

Anyway, here's all the documentation for it -- some sample pubkey filenames and the corresponding derived usernames:

plain username, no multikey

sitaramc.pub                            sitaramc

plain username, with multikeys

sitaramc@laptop.pub                     sitaramc
sitaramc@desktop.pub                    sitaramc

email address as username, no multikey

sitaramc@gmail.com.pub                  sitaramc@gmail.com

email address as username, with multikeys

sitaramc@gmail.com@laptop.pub           sitaramc@gmail.com
sitaramc@gmail.com@desktop.pub          sitaramc@gmail.com