Adjust to use default URI.escape escape list

Conform to RFC per comments on: https://github.com/puppetlabs/puppetlabs-stdlib/pull/164

Conflicts:
	lib/puppet/parser/functions/uriescape.rb
	spec/unit/puppet/parser/functions/uriescape_spec.rb
Merge branch 'uriescape-use_default_escape_list'

This closes GH-164