detect browser speed and downgrade keysize if needed

[benadida]

No description provided.

[shane-tomlinson]

I'm digging this approach, it could mean that we could support some older devices like my ancient iPod Touch that always times out when generating a key - even using DSA.

[benadida]

after some discussion with bsmith, I'm starting to think we may be able to move to 1024-bit keys for everyone, given how short-lived our keys are, and given that they're only signing keys.

[benadida]

barring issues raised on mailing list, action here is to downgrade all keys to 1024-bit, which should be plenty.

[lloyd]

done in train 2012.04.11