Tidy `proxy.js`.

Removed useless return statements.
Tidy.

Wrapped long lines. Checked spelling. Moved commas to end of line.
Upgrade Proof to 0.0.20.
Tidy `proxy.js`.

Wrapped long lines. Removed useless return statements.
Merge branch `proxy` into `master`.
Merge branch `master` into `client-test`.
Minimal test through proxy.

Created a minimal test runs a UDT connection through a proxy. The
connection is between a C++ client and a C++ server to verify that the
proxy itself works correctly.
Merge branch `proxy-test` into `travis-ci`.