qml.Object is now an interface.
Window is now based on CommonObject.
Context is now based on CommonObject.
Move C++ fatal errors into Go space
CommonObject => Common
Support color values and properties as color.RGBA
Fix copy & paste typo.
Fix samples for changes in qml.Object

qml.Object is now an interface, this updates the samples according so
that they keep running.
Merge pull request #10 from oblitum/sync-samples

Fix samples for changes in qml.Object
Allow qml.Changed on unknown values

Otherwise it's hard to create types that work before their
values are added to the engine.
Improved delegate model view example
In-progress Result idea.
Reverted Result. Not enough of an improvement.
Convert int32 to int64 from C++ to Go

This makes writing correct code easier.
int32 => int rather than int64.
Try to fix reported Windows issue (#11).
Better errors on incorrect parameter types

Unfortunately this is a bit hard to put in the test suite
as it is testing a hard crash scenario in the GUI thread.
Better wrapping of values and better errors
Rename ShowWindow as it is used by the Windows API

Slightly better error reporting from C++ would be nice.

Fixes #11.