Remove the "use Devel::hdb" line inserted at the top of the program

It's inserted by the debugging guts of Perl
Get the stack built correctly

Put it in the right order
Don't include calls within the debugger
fixup the sub names at each level
remove unnecessary code
When adding tabs for the stack, make the first one active automatically
Clone the program code div before adding it

This way, the same file can be shown at multiple stack levels, each
with an independant highlited position
program code window style changes

Make the table rows closer together

Make the current position blue instead of green.  This is the same blue
as Bootstrap's "primary" button
Make multiple spaces render properly in code sections