Allow read from file and use echo().

Also change to hex-encoded WKB instead of binary to make streaming
more reliable.
Handle file, stream, or text input.

Also add a CLI test.
Sort JSON keys when writing.

Make sure tox and pep8 are satisfied.
Merge pull request #18 from sgillies/geomet-file-input

Allow read from file and use echo().

Geomet (the script) should now also handle file, stream, and text input transparently.