test PLAIN auth with failed login

This test fails because PLAIN authentication doesn't actually reject connections
test failed CURVE auth

adds expect_bounce_fail test function

which is like bounce, but fails if messages arrive.
Change name of icanhasall to subscribe_to_all

icanhasall is cute (for now), but the effect of the variable is clear
only after tracking down its origin reading the commit. This change is
intended to make it easier for people to have some intuition about its
effect from its name.
Merge pull request #638 from shawnjgoff/master

Change name of icanhasall to subscribe_to_all
Merge pull request #637 from minrk/test_plain_inauth

test failed auth for both PLAIN and CURVE