KVMD 1.78: VNC improvements

Two important VNC improvements: client connections that have hung up are now terminated correctly using TCP_KEEPALIVE; applying the TCP_NODELAY parameter slightly improved responsiveness.

• Improved compatibility with FireFox.

• Minor fixes and codebase cleanup.

This release also updated the list of project sponsors, who donated via Patreon (https://patreon.com/pikvm) or PayPal (https://www.paypal.me/mdevaev). The names of these good people are forever immortalized on the project page and in the web interface in the About window.

Thanks to them, I was able to buy a couple of new devices, support for which will appear in one of the next releases of Pi-KVM, and also bought food for my cat!