Don't shorten URLs shorter than Bitly URLs

[iankronquist]

Whoever calculated the old hardcoded length forgot to include the protocol.

Thank you for improving Hamper!

Check one:

• [x] I remembered to bump the version
• [ ] This is a typo fix and no version bump is necessary

Does this fix an issue?

• [x] Fixes #129

Do you want this change to show up in the LUG hamper?

• [x] I PR'd a version bump to LUG hamper

[iankronquist]

Not sure if we're using the lug hamper repo still, but I opened a PR anyway.