Add support for accessing native settings.

On Windows, provides access to the registry. On OS X, provides access to
arbitrary property list files. On other operating systems, provides
access to arbitrary .ini files.

Task-number: QBS-422

Change-Id: I37aa657db01009d9bd577f51445709957d1fe630
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Don't use the term "Burn" in the WiX module.

What WiX happens to calls its various internal parts is irrelevant to
users; using more well understood terminology now.

Task-number: QBS-413
Change-Id: Iba2359d92d36b0a2e8a78b75d9bed7fec4d728d1
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Add a hostOSVersion property, defined for Windows and OS X.

Change-Id: I04da329f17c54f010fd467841f305d6ab7e922f0
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>