Debugger (fixes #25)

The unicorn. At last.

- [x] Unfortunately, support for pointer vars is really bad at the moment as far as I've tested so this should be improved before merging (if possible)
- [x] default gdb path should work out of the box, maybe we can get away with using just ``` gdb ``` instead of full path
- [x] add version check
- [x] stop process once debugger is stopped
- [x] check that breakpoints work with goroutines
- [x] check that debugger works with an http app

Early access preview download here: https://www.dropbox.com/sh/kzcmavr2cmqqdqw/j8wjp8SdNH (the debugger-.. jar). Please understand this is a beta :)