ehelp: a pedestrian extended help extractor utility

to provide good help is tricky: either it's too little or it clutters the command window with hundreds of lines - and thus becomes unintelligible.

Therefore, it is often desirable to give a user the option of various additional (=extended) help levels that go beyond the classical
> help myfunc

EHELP offers a solution with these simple typical steps
1) the author writes a function
2) at the end, additional help sections are embedded, each between two unique tags
3) the function body of EHELP is copy/pasted into the main function and acts as a subroutine
3) command line options are implemented for a user to look at the extended help
4) EHELP is called (typically within a switch-yard based on input options) to extract the appropriate section from its main function

EHELP can be used as a command line tool if the author provides appropriate information within the classical help section

use of low-level i/o functions guarantees a very quick extraction

see the accompanying published ML file for a simple example