Plug-ins focus in SONAR

[azslow3]

SONAR exposes several functions to change the focus. That affect ACT mapping and can affect visualization, especially in the latest versions which by default switch plug-in UI to currently focused one by default.

Unfortunately, the logic of what is "Next"/"Previous" as well as what is PlugIn UI is not consistent with introduction of ProChannel.

The whole picture:
* No mapping, no FX plug-ins exists in the project, some ProChannel modules exists (but not focused). "Next"/"Open" does nothing, "Previous" crash SONAR...
* No mapping, some FX plug-ins exists in the project. "Next"/"Previous"/"Open" change to FX plug-in, or do nothing.
* Some FX is focused. "Next"/"Previous"/"Open" work as expected, within the project (focus moves between plug-ins in different tracks)
* Some Synth is focused. "Next"/"Previous"/"Open" work within the Synth Rack
* Some ProChannel is focused. "Next"/"Previous" work within this strip ProChannel modules. "Open" opens some internal UI or crash the module.

Note: Control Surface API has no function which return what is currently focused in term of plug-in/parameter. There is no way to detect from which strip currently focused plug-in is.

Note: AZ Controller tries to avoid crashes, other plug-ins do not.