Add highlight faces

Added some faces for the user to use for highlights, so they don't
have to define their own right away.
Partial implementation of using prompt regexps

Added character and password prompt regexps to the world vector
`defcustom', and changed `mu-login' and how it's called to use prompt
regexps if set, otherwise send the "connect" command to the server.
Actually using prompt regexps is yet unimplemented.
Merge branch 'master' into login-regexps
Fill in `mu-login'

Filled in `mu-login' case where called as an output-filter function.
Still won't work because it depends on the current world being bound
to a (buffer-local) variable.
Merge branch 'master' into login-regexps
Use login-prompt regexps

When connecting to a server, if the given world specifies either a
char- or password-prompt regexp, send the character name and password
when a line matching those is received, instead of just send int the
name and password via the "connect" command, which doesn't work on all
servers.