Add support for multiple qface files in QFACE_SOURCES

For supporting bigger pojects which need to combine several modules it makes sense to support building these modules into one project.

E.g. a the navigation part of a project consists of serveral qface files with several modules which should be build all together into one library. To support this the following is needed:

• add namespace to all headers/sources
• ensure all meta-type related types a fully qualified types
• ensure all types are registered with namespaces
• ensure qml types are registered per module
• update qmake feature to support list of sources
• update ivi generator to support more than one qface document

The final goal is to support this for all templates. For templates which also have their main.cpp e.g. the server templates, the templates need to be changed to generate the main.cpp only once and support instantiating all modules.