perl plugin: Added "EnableDebugger" config option.

perl plugin: Added "EnableDebugger" config option.

This config option will pass control to the Perl debugger after the
interpreter has been initialized. This is exactly the same as invoking perl
with the "-d" command line switch.

Just as with perl's "-d" command line option you can supply an alternative
debugger. Pass the package name as an argument to the "EnableDebugger" option

See perldebug(1) for more details.

Signed-off-by: Sebastian Harl <sh@tokkee.org>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>