Update metadata.json: fix dependency for stdlib

Modulefile previously depended on >= 3.0.0.
Merge pull request #55 from codec/fix-dependencies

Update metadata.json: fix dependency for stdlib
Fix missing  parameter
Merge pull request #57 from eshamow/fix_misten_listen_variable

Fix missing listen parameter
Linting metadata.json
Merge pull request #54 from puppet-community/lint_metadata

Linting metadata.json
Description for rake task for metadata
Merge pull request #60 from puppet-community/rake_desc

Description for rake task for metadata