Essential features

[gsmcmullin]

• [x] being able to configure it (aka able to setup a remote session with black magic)
• [x] being able to access the gdb command line
• [x] highlight the code line in the text editor where we are at the moment
• [x] start, continue, next, step, finish and interrupt accessible from UI
• [x] indicate where breakpoints are set
• [x] provide a way to display watchpoints
• [x] provide a way to display variable contents by moving the cursor in the text editor over a symbol
• [x] popup backtrace allowing user to select frame
• [x] sensible default keybindings
• [x] allow user to assign new values to variables