Ensure purge on /etc/diamond/collectors

It is undesirable to have non-Puppet managed collectors in /etc/diamond/collectors, so since we provide a way to manage those, we should purge any which aren't
Update install.pp

Add dependency on /etc/diamond and create that directory
Update install.pp

Add ownership to /etc/diamond and /etc/diamond/collectors
Parameterise purging diamond collectors, defaulting to false
Ensure consistent use of purge_collectors parameter
Add tests for purge_collectors parameter and lack thereof
Merge pull request #12 from vulpine/master

Ensure purge on /etc/diamond/collectors
bump version
add source to Modulefile
initial commit for pip install on RedHat
added case operatingsystem for python-dev or python-devel
fixed typo
fixed 2 spaces soft tab
use of package instead of ensure_packages
more fixes for Travis - sorry I'm discovering puppet-lint a bit late
added some tests and fixed a typo
use of facts instead of params
added Ubuntu and Debian tests for install_from_pip
changed operatingsystem by osfamily fact, and use ensure_packages on package deps
added include epel