Add --no-reinstall option flag.
Add period to end of indented explanation.
Added a CONTRIBUTING.md file.
Added another thing to the CONTRIBUTING.
Merge pull request #39 from stefanozanella/skip_deps_option

Add option to skip installation of build dependencies.
Renamed SKIP_DEPS to SKIP_INSTALL_DEPS.
Style.
Added the --md5 option (closes #14).
Updated the man pages
Renamed "Supported Rubies" to "Known Rubies".
Wording.