Qt Wayland Surface Id Generation

Currently the QtWayland IVI id patch expects hard coded surface ids to be passed as a property of the QWindow. Obviously this is bad as all the apps need to know about the ids of other apps to avoid a conflict. It's also bad because an application that would normally run outside of the IVI needs IVI layer manager specific code even though it's not using any specific features of the IVI layer manager.

I have updated the IVI id patch for QtWayland to automatically generate an id for a window if the magic IVI-Surface-ID is not already set. The id formula is (PID_MAX + (PID * 500) + NumAppSurfaces). PID max on Linux being 2^22. This formula allows for plenty of room for ranges of IDs that do not overlap. This id is passed back to the Qt Window using the magic IVI-Surface-ID if the app ever needs to use it with ILM directly. Only then will an app need to contain this magic string. For the vast number of use cases the app won't need to access the layer manager directly.

In the new patch if an app passes an IVI-Surface-ID that is still respected. If an app asks for a surface 2^22 there could be conflicts. Unlikely, but possible. Best to document (2^22)-1 as the limit to user specified surface ids