Remove "range matching" functionality

Don't support "range marching" in our pattern matching code using
the "[...]" syntax, because [ and ] are valid characters in nick
names and one has to quote them currently using the "\" character,
which is quite unexpected. For example:

  Nick "te[st" => "MODE #channel +b te\[st"

And remove quoting altogether, too, because "*" and "?" don't need
to be quoted because these characters are not allowed in IRC masks,
nicks, and hostnames.

Reported by "hifi" (Toni Spets) on IRC, thanks!
Use $(MKDIR_P) instead of $(mkinstalldirs) in Makefile's

And test for "mkdir -p" using AC_PROG_MKDIR_P in "configure".
Merge branch 'no-range-matching' of git://arthur.barton.de/ngircd-alex

* 'no-range-matching' of git://arthur.barton.de/ngircd-alex:
  Remove "range matching" functionality