QmlJS: Rework exported C++ type registry.

The problem was that if you exported
A 1.0, A 1.1 and B 1.0 where A is the prototype of B
the code model had not enough information to know that, depending
on the import, B 1.0's prototype should be A 1.1 or A 1.0.

To solve this problem QmlObjectValues now store the import's version
as well as the local component version. In the example above B 1.0
would have import version 1.1 if the 1.1 module was imported and thus
be able to choose the right prototype.

Change-Id: I7ef33f12ca5a528c62b2a8240f4b5720b0ebd4c3
Reviewed-on: http://codereview.qt-project.org/5129


Reviewed-by: Thomas Hartmann <Thomas.Hartmann@nokia.com>