Better Completion

Added precompiled binaries for maxOS ARM64 (Apple silicon) and OpenBSD MIPS64.
Replaced 'builtin' with 'fn'. This should make the story of oh's facilities for abstraction easier to tell.
Completion now "cheats" and uses bash, if installed, to supply completions.
Wrapper for 'ls' is no longer declared if 'ls' does not support the '--color' option.
Fixed regression that prevented passing command-line arguments to oh scripts.