Minor optimizations, build, and documentation changes

What's Changed

• Use optimized linux byteswap macros if available. by @kevin-vigor in #53
• Fix "No such file or directory" when launched with empty fd 0. by @kevin-vigor in #55
• Negative cache failed lookups. This saves a FUSE operation when by @kevin-vigor in #56
• Split squashfuse_ll into a lib and executable by @haampie in #59
• Remove redundant #if in ll header by @haampie in #61
• Add CI for NetBSD by @vasi in #62
• Move CI away from Travis by @vasi in #63
• Update FreeBSD CI job to build on 12.3 by @emaste in #71

New Contributors

• @kevin-vigor made their first contribution in #53
• @haampie made their first contribution in #59

Full Changelog: 0.1.104...0.1.105