Lots of man page fixes and some other minor fixes (#284)

Noteworthy changes:
- The man pages have been updated to fix a ton of instances of
  runaway underlining (this was done with `sed -i 's/\\f5/\\f3/g'`
  commands). This commit dramatically increased in size because
  of this change.
- The documentation for spawnveg(3) has been extended with
  information about its usage of posix_spawn(3) and vfork(2).
- The documentation for tmfmt(3) has been updated with the changes
  previously made to the man pages for the printf and date builtins
  (though the latter builtin is disabled by default).
- The shell's tracked alias tree (hash table) is now documented in
  the shell(3) man page.
- Removed the commented out regression test for an ERRNO variable
  as the COMPATIBILITY file states it was removed in ksh93.

src/cmd/ksh93/data/builtins.c

@@ -732,11 +732,11 @@ const char sh_optgetopts[] =
       "[+n?Associate -\anumber\a and +\anumber\a options with the first "
         "option with numeric arguments.]"
       "[+o?The \b-\b option character prefix is optional (supports "
-        "obsolete \bps\b(1) option syntax.)]"
+        "obsolete \bps\b(1) option syntax).]"
       "[+p?\anumber\a specifies the number of \b-\b characters that must "
 	"prefix long option names. The default is \b2\b; \b0\b, \b1\b or "
 	"\b2\b are accepted (e.g., \bp0\b for \bdd\b(1) and \bp1\b for "
-	"\bfind\b(1).)]"
+	"\bfind\b(1)).]"
       "[+s?\anumber\a specifies the \b--??man\b section number, "
         "\b1\b by default.]"
   "}"