Fixed HPACK decoder dynamic table size limit

• Update ls-hpack to 2.3.0 to properly enforce decoder dynamic table size limit (issue #260).

Fix uninitialized member, high CPU usage and h3spec

• Fixed an unintialized data member for handling pushed headers.
• Added a new status code for version negotiation failure.
• Fixed a few compliance issues found by h3spec.
• Addressed high CPU usage when transport cannot send pending packets.

Fix high CPU usage, SIGFPE; multiple headers support

• Added support for sending/receiving multiple headers to address the case related to "100 continue" header handling.
• Addressed high CPU usage for a GOAWAY connection before sending CONNECTION_CLOSE.
• Addressed SIGFPE due to zero pacing rate. (ISSUE #254).
• Fixed a minor issue related to multi-paths.

Internals docs; h3spec and other fixes

• Documentation: describe lsquic internals ("guts").
• Two more fixes to compliance issues found by h3spec.
• Truncate, don't abort, SCIDs larger than 16 bytes (PR #244).
• Several small internal improvements and space optimizations.

Better HTTP/3 standard compliance

• Fix a few issues detected by h3spec for better compliance with HTTP/3 standard.

Bug fixes: push promises, misput HQ frames

• [BUGFIX] Infinite loop in stream: returned HQ frame can be at any point on the list.
• [BUGFIX] Fail push promise immediately if STREAM_NOPUSH is set.

Bug fixes: push promises, misput HQ frames

• [BUGFIX] Infinite loop in stream: returned HQ frame can be at any point on the list.
• [BUGFIX] Fail push promise immediately if STREAM_NOPUSH is set.

Bug fixes, minor improvements

• [BUGFIX] Do not send RESET_STREAM if writing to stream is already finished.
• perf_client: wait for all ACKs before exiting.
• Improve how generated RESET_STREAM is logged.
• Fix compilation in different combos of adv_tick/conn_stats flags.
• Move qpack warning disablement into src/liblsquic/CMakeLists.txt.

Fix gQUIC server handshake regression

• Fix regression in gQUIC server: bug #234.

perf utils; build improvements

• Make it possible to build the library and unit tests without libevent.
• Build all command-line utilities in bin/
• Add perf_client and perf_server command-line utilities to test performance according to the "perf" protocol.