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
Merge branch 'master' into profiler

Conflicts:
	checks/ganglia.py
Merge branch 'master' into profiler
Merge branch 'master' into profiler

Conflicts:
	.gitignore
	Vagrantfile
	packaging/datadog-agent-deb/postinst
	packaging/datadog-agent-rpm/preinst
Left-over import
Merge branch 'profiler'