Necessary for debugging with a remote gdb (as opposed to gdbserver).

Reviewed-by: kh1

Use Debugger::DebuggerRunControl directly instead of wrapping it
into another RunControl.

Reviewed-by: hjk

Written-by: hjk

This mainly allows for more precise shutdown and tightens the set
of allowed transitions.

This updates the state diagram in debuggerplugin.cpp and
renames AdapterStart{Fail}ed to EngineStart{Fail}ed.

Still far from usable.

CDB: Add more information and state to Thread.
Refactor thread information in CdbCore classes to prepare for more
information.

Reviewed-by: hjk

Store threads and cache registers per thread in Snapshot.
As Trk does not generate Thread creation/deletion events.
try to add threads on the fly if a stop in a new thread id is reported.
Remove them in continue. Continue all threads in classic Trk.
Pass on state (crash reason) to ThreadData and model.
Factor out common code of both adapters to Snapshot/Symbian classes.

(cherry picked from commit 6959a122)

Conflicts:

	src/plugins/debugger/gdb/gdbengine.cpp
	src/plugins/debugger/gdb/gdbengine.h

(cherry picked from commit ebba2748)

Conflicts:

	src/plugins/debugger/gdb/gdbengine.cpp