just require vagrant-cachier

the respond_to? guard wasn't working properly
no more static ip reliance, thanks to landrush 0.6.0

just a hostname is all landrush needs to do its thing, so we can remove
our embarassing hack for unique ips
support dirs with spaces or underscores

those characters aren't valid in hostnames, so change them to hyphens
allow database flavor config to be empty
don't become root by default in ssh