* Add the ability to specify an install_dir to the gem module
* Add GEM_HOME when installing a non-global gem
* Add tests for custom gem path
* Fix sanity tests
* Add changelog entry
* Rebase and add tests for incorrect options
Co-authored by: Antoine Catton <devel@antoine.catton.fr>
This change corrects problems reported by the `yamllint` linter.
Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.
