#3 ssm help window improvement

[Anonymous]

From Boo-boo (boo_boo@inbox.ru)

I'm new to ssm, and need to read plugin help often. But
opening help window few times typically leads to
segfault - coz Fl_Text_Display widget is too heavy and
somewhat buggy to create it once again for each new
help text. Also, pressing `?` on another plugin when help
is active, works strange... And, finally, help window don't
remember its old position when called again.
So i've slightly rewrote SpiralPluginGUI class to share
one help window between all plugins. '?' behavior also
fixed.

[Nobody/Anonymous]

ssm help window improvement