Implement support for using strace/ltrace as debugger:
- Add parameters "--ltrace" / "--strace"
- Also add parameter "--gdb" if someone wants to explicitely specify to use gdb in case it might not be the default anymore in the future
- Adapt syntax printing to the new syntax
- Fix documentation of global variables
- Sort parameters in parser alphabetically
- Adapt debug code to new syntax
- Encapsulate debug command construction in a function
- Don't enumarate global variables in documentation of main() to prevent people from having to maintain the variable list in two different places