Fail with osfamily message, not operatingsystem

Since our case statement is evaluating the $::osfamily fact, our fail
message should report THAT instead of $::operatingsystem.
Validate runuser parameter for x11vnc

This commit validates that the value for the 'runuser' parameter is a
string.
display::env should inherit params

Since we're setting the 'display' parameter to a default obtained from
display::params, we need to inherit this class.
Validate the display parameter in display::env

This commit validates that the value for the 'display' parameter in
display::env is an integer.
Add rspec-puppet tests

This commit adds rspec-puppet tests for the display module.
Merge branch 'unit_testing'
Prep for travis-ci testing
Trigger travis? jeez.
Unfuck fixtures GH address
Merge branch 'master' of github.com:p0deje/puppet-display