Extra testing to ensure accidental downgrades aren't happening
Test against puppet 3.6.0
Bump the metadata.json now that compatibility has been verified
Simplify licensing

We are dropping multi-licensing in favour of adopting Apache 2.0,
this is what Puppet uses, and this ensures everyone using puppet
can confidently use PortageGT. We are able to relicense it thanks
to our CLA which enables us to sublicense all contributions however
we see fit.
Fix some of the new rubocop guidelines
Bump puppet 3.5 version for travis to use
3.6.2 is now the only compatible version in the portage tree, so we should test against it.

Also clarify the installation process.
Warn the user when they set use => ['flag', '-flag'] and don't change anything.
Fix other places where the license wasn't updated.
Fix failure to reinstall packages when removing default use flag
Fix a typo in the readme
Correct another typo in the readme
Minor, rubocop suggestions
minor cleanup
Merge branch 'master' into refreshable

Conflicts:
	.travis.yml
	metadata.json