Use Qt::Dialog instead of Qt::Tool which works better with window
activation / deactivation handling.
Stop displaying the panel on all spaces when the call is established.
Don't deactivate the application when the main window is hidden.
Such behavior provides some unwanted windows reordering in the
current workspace when the window is hidden by Cmd+W.
Ignore app activation by applicationDidBecomeActive: notification
for a short period of time after a user notification for other app
instance was received (the system sends them sometimes and the main
window is shown + activated for a wrong instance of the application).
Now each platform-dependent module declares its interface in
platform/platform_module.h file and after that includes platform-
specific headers like platform/win/module_win.h with implementation.
Also removed the legacy WinRT platform-dependent implementations.
A regression was introduced in 1.0.12 version which led to wrong
activations of the main window: if a custom popup menu was shown
for the tray icon or a custom notification was clicked.
