Changed the mount_encrypted_home_dirs script (and renamed it)

My mount_encrypted_home_dirs script was working perfectly, except for
one slight oversight - root can't mount encrypted user home directories
without having a password for every username - the only reason it kept
working for me was because all of my test users (including root) were
all using the same password. The way I thought I had it working is
apparently impossible, according to the author of Ubuntu's Encrypted
Home Directory feature, and the current maintainer of eCryptfs:

"when your home directory is not mounted, the root user would
need your login passphrase (or, more specifically, your randomly generated
mount passphrase) in order to mount and decrypt your data."
-- http://askubuntu.com/a/107327

This new code makes it easier for a user to mount encrypted user home
dirs than doing it manually