Drop dependency on dpatch

We no longer need dpatch, now that we have migrated everything
we care about to source format 3.0 (which requires quilt for
non-native packages)
Remove dependency on devscripts-el

The devscripts-el package is broken (Trac: 1468), so we remove it.
Anyone who actually wants to run debuild inside emacs should go
install it themselves.
Release version 0.6

Release a new version of the package that eliminates
dpatch and devscripts-el from dependencies