a standard library in Finch: path, time, proc, json

import json   import path   import time   import proc  -- found in std/ after the program's own files,
so a program's own json.fch always wins.

path: join, base, dir, ext, stem, parts, clean, is_abs.
time: now, millis, sleep, date, local, format, days_in_month (clock_gettime, strftime through C import).
proc: run, output (an error with the command's output when it fails), env, pid, cwd.
json: parse (errors with line and column), stringify, pretty, new_*, get/at/set/push/has/names and
str_or/int_or/float_or/bool_or; \u escapes with surrogate pairs.

The C importer now leaves a plain (non-const) char * parameter a ptr[char], a buffer C writes into;
only const char * is text going in. str(ptr) and str([]u8) are in the self-hosted compiler.

boot.sh: 40 passed, 0 failed.

tests/new/std_time_proc.out

@@ -0,0 +1,9 @@
+1971 1 1 1 1 1 5 1
+29 28 28 29 30
+true
+true true
+hello
+world
+3
+'echo oops; exit 2' exited with code 2: oops
+fallback true true