* Use id() for methods returning a string used to represent
    some type of object.
  * Use displayName() for strings that are meant to be user
    visible.
  * Quieten some warnings while touching the files anyway.
  * Move Factories to their products in the plugins where that
    was not done before.

Reviewed-by: dt

Separate category and trCategory and introduce sorting characters
to the categories. Same for id/name.

Display the error in a label of the preferences page.
Reviewed-by: con

- Introduce a communications device type flag, add stubs for
  Bluetooth to serialdevicelister and pass the device type
  in new struct CommunicationDevice along to run configuration
  and debugger start parameters (overriding the debugger settings).
- Give the s60devices::Device a tooltip in the settings page