changed .count to .size to support legacy ruby
Merge branch 'master' of git://github.com/puppetlabs/puppetlabs-stdlib
check if an argument supposed to be merged is empty to
pass over undefs without failing
fix in merge.rb: refine the checking if an argument is an empty string
Added rspec tests for the new behaviour of merge accepting empty strings

added test that '' is accepted
changed a test that a number is correctly rejected with a type error
(#20684) Add array comparison functions, difference, intersection and union.

Included is code, tests and documentation for the difference, intersection
and union functions for comparing arrays.
Merge pull request #147 from mhellmic/master

don't fail on undef variable in merge
Merge pull request #155 from AlexCline/feature/master/array_comparison_functions

(#20684) Add array comparison functions, difference, intersection and union