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.

fixes #133

Add a test support package which allows shared test functionality
for both the unit and integration tests.

Tests importing the proctl/test package will gain access to a special
test entrypoint which precompiles fixtures and makes them available
to tests.

This information is hardly going to be useful to a user of Delve and if
the user really needs information on new threads they can simply using
the provided commands to list and switch between threads.

Eliminate a race condition in TestHalt where the RequestManualStop
call can precede the Continue call, causing the test to sporadically
fail.