We should restrict ourselves to calling all qml debugging support
observer, instead of mixing qml debugger / inspector / observer
interchangeably.

Unify terminology somewhat.

The class extends the QDDebugService class, _not_ QDDebugServer. It's
right that there is also a QDEngineDebugServer being actually a service
in QtDeclarative, but we should probably fix this one too.

Also introduce a indirection, modes have now types, edit and debug have
the same type, and editors do have a prefered type of modes instead of a
prefered mode.

That fixes the bug that if the prefered qml editing mode was set to
design, then in switching between qml editors would
- in Edit Mode: stay in edit mode
- in Debug Mode: switch to debug mode

namespace (from Debugger::Internal) as they are exported classes.
Introduce private classes to avoid exposing private JS debugger
headers.

Reviewed by: Lasse Holmstedt

Did not work e.g. for projects where non-project files are loaded.

This happened if the file is openned after the debugger has started

This should speed up the matching between the AST nodes and the debugIds

 * Fix all warnings about non-explicit constructors except for those
   in 3rdparty code.

It was not very useful without being able to e.g. move things around.

Animation play/pause buttons are now merged on observer toolbar. Also, a
bugfix to inspector toolbar.

There is now a hook in QDeclarative itself for that.
Needs commit af2b28f9ca07057 of Qt

Reviewed-by: hjk

Creating LookupContext seems to be expensive, so don't update anything
unless debug mode is already running.

Easier to use now by just clicking on one button, and takes less space.

A new debugger engine, QmlCppEngine, is introduced, which wraps gdb
and qml engines into one. Alternatively, if using Windows, Cdb is used
instead of Gdb.

Most of the debugger ui switcher is now rewritten, and it is tailored
for the QML and CPP layout case, the only one supported anyway.

Reviewed-by: hjk

The problem was that we did not query the object with the good engine id

+ add missing tr()

Now, QmlEngine creates the connection to the inferior (debuggee), and
notifies QmlInspector when a connection is established. Before,
inspector created the debugger engin, which was wrong.

QmlEngine's responsibilities are connecting to the debuggee and basic
QML/JS debugging features like locals & watchers, breakpoints etc.
QmlInspector takes care of Live Preview and other fancy inspection
features.

Reviewed-by: hjk

For starters, we only remember whether the initial warning about dangers
of Live Preview was shown.