Task-number: QTCREATORBUG-598

A mostly mechanical change.

Reviewed-By: con

This replaces the (de facto) singleton engines and data handlers by classes
that are instantiated per run. The DebuggerRunControl will now create an
object of (a class derived from) DebuggerEngine that contains all the relevant
"dynamic" data.

DebuggerManager is no more. The "singleton" bits are merged into DebuggerPlugin,
whereas the data bits went to DebuggerEngine.

There is no formal notion of a "current" DebuggerEngine. However, as there's
only one DebuggerEngine at a time that has its data models connected to the
view, there's still some "de facto" notion of a "current" engine. Calling
SomeModel::setData(int role, QVariant data) with custom role is used as the
primary dispatch mechanism from the views to the "current" data models
(and the engine, as all data models know their engine).

Discussed-with: hjk

The current northpointing dockwidget layout looks
broken since we repeat the label when the docks are
unlocked. We also dont line up properly with the header sections.
Other dock widgets in designer are also using the south tab so
this would be more consistent.

Reviewed-by: danimo

Move actions into FancyMainWindow. Register them in
DebuggerUISwitcher and FormEditorW. Manually hide
Debugger actions for Non-Debug modes (as they belong
to the language context).
Acked-by: con

It's not yet possible to attach to an external app running a qml
debugging server, because the server is only started on startup if an
env variable is set. Changing this requires action from Brisbane, but
even the current solution works for C++ apps with QML in them.

Task-number: BAUHAUS-585
Reviewed-by: dt

Task-number: QTCREATOR-202
Reviewed-by: hjk

Prevent window from popping up repeatedly on warnings.
Task-number: QTCREATORBUG-1061

Reviewed-by: Thorbjørn

While before you had to call add, then remove for each context id and
then call update, now you call updateAdditionalContexts with a list of
contexts to remove and add. It has the update step built in.

Reviewed-by: con

the previous implementation relied on poking around with setVisible
of the menu actions. Now, command attribute CA_Hide is used instead for
the necessary entries.

Reviewed-by: hjk

Additionally, hiding of debugger menu entries was done as most of
them are irrelevant for QML debugging.

The new QML Inspector depends on DebuggerPlugin. Also added a dropdown menu into
the debugger toolbar from which the user can select the used debugging
language, e.g. C++ or QML.