Start of implementation of interactive debugger
A bit more of the debugger mode
fixes #250, haskell-interactive mode broken under certain conditions
Good progress on debugger stepping
Keep hold of the back trace for helpful display at the end
Debugger with bindings display
Re-step after reloading
Reset history and bindings cache after abandoning
Support next/previous properly
Add back 'break properties to breakpoint list
Make haskell-interactive-at-prompt return position

Instead of bool
use notify instead of notifications-notify