kcptun-libev v2.2

Changes since v2.1.2:

1. [crypto] Add xsalsa20poly1305.
2. [obfs] Faster connection setup.
3. [queue] Batch ack flushing.
4. [server] Better stats format.
5. [security] Fix possible crash caused by invalid HTTP requests.

Check README for more information.

If you downloaded a *-static build, you don't have to install runtime dependencies.

Full Changelog: v2.1.2...v2.2