Initial debugger work.
Merge branch 'release-poc-4' into debugger

Conflicts:
	alethzero/MainWin.cpp
	alethzero/MainWin.h
	libethereum/Common.h
Merge branch 'develop' into debugger

Conflicts:
	alethzero/MainWin.cpp
	alethzero/MainWin.h
Debugger.
Merge branch 'debugger' into develop