Whitespace & caps.
Need explicit adminUser & adminPass, instead of randomly gen'ed.

I discovered a previous change of mine broke the feature of printing
out the randomly generated admin password.  On further thought, a
generated password didn't seem highly useful.  Instead, error'ing
unless the adminUser/adminPass was either both or neither (with a
hopefully not-overly-annoying warning message when they're not set)
seems more operator friendly.

Also, adminUser/adminPass can now be specified via CBGB_ADMIN_USER /
CBGB_ADMIN_PASS environment variables to hide those values from tools
like ps.