multiple debugger support

[bombasticbob]

X11workbench should support multiple types of debuggers. This should include:

• gdb
• bash (or sh)
• perl
• php

existing programs like xxgdb and ddd can be examined as to how to easily implement something like this. Care must be taken NOT to 'derive' anything, to avoid licensing issues (ddd is GPLv3).

for gdb, the application needs an easy-to-use GUI method by which you can send a debugging command and receive back debug information, for this to work at all.

Additionally, you should be able to interactively examine code/data and issue gdb commands (such as backtrace, print, single-step, and stack frame selection), and implicitly issue certain commands (like info, list, and enabling or disabling breakpoints).

shell and perl debug needs to interact similarly with their respective interpreters.