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/sh/main.c

@@ -186,7 +186,7 @@ int sh_main(int ac, char *av[], Shinit_f userinit)
 #if SHOPT_REMOTE
 		/*
 		 * Building ksh with SHOPT_REMOTE=1 causes ksh to set --rc if stdin is
-		 * a socket (presumably part of a remote shell invocation.)
+		 * a socket (presumably part of a remote shell invocation).
 		 */
 		if(!sh_isoption(SH_RC) && !fstat(0, &statb) && REMOTE(statb.st_mode))
 			sh_onoption(SH_RC);