New source installation script

	* High level logging
	* Dependency check (sysstat and python)
	* Better failure handling
	* Automated reporting (needs user approval)

Fix #476 Fix #473 Fix #378 Fix #139
Fix conflicts
Do not try to log in /var/log for source installation
Fix #478
Add some useful comments
Some cosmetics
Merge branch 'master' into new_source_install_script
Remove a last empty line
Some cosmetics
bin/agent is more informative now, info is a subcommand
Fix bash test

In case supervisord is not running.
Merge fix for #497

Conflicts:
	packaging/datadog-agent/source/agent
	packaging/datadog-agent/source/info
Pin nose version in .travis.yml
Some improvements according to the review
Merge with master
Fixing reporting url
Get better bin/agent and bin/info commands
Make info an executable
Make info script executable
Merge pull request #485 from DataDog/new_source_install_script

New source install script