Hardware breakpoints are by definition architecture dependant. Move them
off the DebuggedProcess struct and onto the associated arch struct.

* Set hardware breakpoints on all existing threads
* Set hardware breakpoints on any new thread the spawns

Fixes #111

* Remove half baked CallFn implementation.
* Cleanup whitespace
* Cleanup read/write mem functions

Prevents leaving around a bunch of zombie processes

Process is an incorrect name for the DebuggedProcess struct that the
thread is "a part" of. Also, no need to export that field.

* Simplify
* Add links to wiki pages
* Add link to CONTRIBUTING doc
* Update description

fixes #133

Added help in commands