HyperSubFunHelp

Display expandable help of nested and subfunctions in an Mfile with recursive behavior

HYPERSUBFUNHELP displays help of a file with expandable recursive subfunctions help
HYPERSUBFUNHELP(MFILE) displays the help of MFILE with expandable help
for each nested/sub functions that are preceeded by a line of comment
containing the key expression '% Display Help'

A set of links is generated containing the name of a sub functions and a
the h1 line of every subfunction.

The expension of one link results in the following displays:
- a link for retracting the subfunction help,
- the subfunction help,
- links for expanding subfunctions of the current subfunction are
displayed (recursive behavior) provided that the subfunctions are
preceeded by a '% Display Help' Tag.

HYPERSUBFUNHELP(MFILE,'short') does not display the main help.
It is usefull for including a link in an Mfile help that adds links to
subfunction help beneath the main help, without repeating it.

Note 1: The depth parsing of subfunctions is based on the indentation
(spaces). If the mfile is not properly indented, the function might not
work.