Ianthehenry Sd Versions Save

• fix a bug where --help would print every comment in the script

• better error message if ~/sd does not exist
• better error message if ~/sd exists but is not a directory

No functional changes from the pre-1.0 releases; just added a license file.

With the addition of per-directory templates, improved autocomplete, and a lighter runtime footprint, I am ready to call sd suitable for real-world use.