Add profiling and POST size stats

Enable collector profiling by adding profile: yes in `datadog.conf`
Re-introduce raise statement that was removed by mistake
Fix per pull request comments
Ignore Vagrant
Simple cosmetic logging fix
haproxy - Calculate used session percentage

Calculate the percentage of used sessions (spct) from the current number of sessions (scur) and the session limit (slim).
haproxy - Catch divide by zero
Don't puke on archives

raise `Skip` and continue on cleanly when coming 
across jobs that have builds which have 
been tar'd up.
Merge branch 'master' into profiler

Conflicts:
	checks/ganglia.py
Do not allow dd-agent user to shell in
Remove dd-agent user and group on uninstall
Turn ssl validation of http_check into an option

Fixes #770.
Merge from master.
Revert source install `set -e`
#768 dd-agent is not part of any group on debian
Vagrant VM for development
Add a centos test box
Fix provisioning on redhat
Redhat package cleans up after itself
Make sure python is on debian7.1 to run the agent
TAB -> spaces in http_check.yaml example