Allows compiling a test binary and debugging it.

Notable changes:
* OS X support
* Pure Go readline library
* Fixes issues debugged cgo enabled programs
* Substantial refactoring / code cleanup

Fixes #3 #29 #70

Currently Travis supports only Ubuntu 12.04 linux 2.6 VMs which are
terribly outdated, and trying to track down why it's hanging on Travis
but not on other similar VMs is more trouble than it's worth at the
moment.

Certainly another more appropriate and up to date CI solution should be
explored.

Add docs for continue

Implement feature that enables the debugger to be able to compile, run
and attach to a program all in one simple step.