To match other modules example directory structures we should deploy our
examples in a directory matching the module name, webengine and
webenginewidgets in our case.

qmake uses the relative directory of each example up to the upper "examples"
directory to decide where they will be deployed when running the sources
install target.

Change-Id: I59ce7ff8a30f98fad20064c7eecf72b784f1d275
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>

This example hasn't been touched since we imported QtWebKit examples.
If we need to have a more test-purpose widgets browser in the future,
we can dig it back from the history.

Change-Id: Icee9bd7f09827a97b33c6783b87311e331d963b1
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>

Cleaner than deciding on startup with an env variable

This layers things properly to be able to implement the UI in the
example application instead of directly in shell_qt.cpp.

This is still using global variables to allow the Shell platform
code to do callbacks to the API classes. This should go away once
we properly implemented a WebContentsDelegate.

We need to replace this with a properly dynamically generated list
of dependencies, but for prototyping this will have to do the trick.