Merge pull request #27 from portertech/windows

[windows] use a newer rubyinstaller devkit release
[init] set_sensu_path() after system specific PATH
[init] amazon == rhel
Merge pull request #29 from portertech/init

Fixed Sensu PATH, attempt to support Amazon Linux AMI
[extensions] add an etc dir for extensions
Merge pull request #30 from portertech/extensions

[extensions] add an etc dir for extensions
[runit] fleshing out the runit recipe
[runit] adding /etc/sensu/services directory
[runit] adding runit to included software
[runit] use erb template for DRYer run scripts
[runit] adding scripts for runit process supervision
[runit] ensure sensu-ctl is linked in /opt/sensu/bin
[runit] fix runit source md5sum check
[runit] making sensu-runsvdir.sh defaults conform to new defaults-driven behavior
[runit] use $PLUGINS_DIR and $HANDLERS_DIR when setting path in sensu-sv-run.sh.erb
[runit] removing -b flag from options in sensu-sv-run.sh.erb
[runit] moving all the runit directories under /opt/sensu
[runit] modify pkg scripts to ensure correct ownership of /opt/sensu/sv
[runit] don't use chpst when starting runsvdir

If runsvdir is started as a non-root user, it won't be able to use
  chpst to change the effective uid when starting any subsequent
  services, even if the effective uid is the same as the one runsvdir
  is running as.
[runit] use $SENSU_USER instead of $USER in sv run script

Many other programs look at $USER env var to figure out who they are
running as. Let's avoid any weirdness and use $SENSU_USER instead.