add prefix and bindir configuration options

add more options to control the layout of the server.
plugins can no longer be configured globally

a new defined type, trafficserver::config::plugin, can from now on be
used to configure plugins individually.

XXX: This is still failing on augeas level, and I have no idea why :C
remaps now rendered as augeas hashes, not arrays

rather than always rendering remaps as array, and hence after a chain of
changes ending up with *one* line per map, we now render it as hash,
which makes it easy to add new or remove old rules, by simply refering
to it via the URL which is being remaped.

We also switch from using an inlinetemplate() hack to simply exposing a
Ruby Hash method.
only reload traffic server when necessary

rather than restarting the daemon, we run traffic_line -x when a config
file has changed.
Version 4.0.1 & later come *with* gzip plugin

The new release of Apache Traffic Server (v4.0.1) considers gzip to be
stable. The package we build contains it per default and does not have
to be installed seperately.