Removed `-format string' switches but made -form accept `=formatstring'.

Removed `-format string' switches but made -form accept `=formatstring'.
For all tools that take `-from file' or `-format string' switches, those
were merged: `-format string' went away, but one may supply any such string
to the -form switch by prepending it with an equal sign `='. Thus
	scan -format '%(msg) %{from}'
is now written as
	scan -form '=%(msg) %{from}'
Note: mhl isn't adjusted this way, yet. It's too complex to be understood
by me, now. Thus, it still remains as it was: Any parameter to -form will be
interepreted as a filter *file*. As show and mhshow use mhl, they are
affected, too.

In the same go: Compactified the new_fs() function: folded the arguments.