Be compatible with GIRepository-1.0 and 2.0.

[mtwebster]

ref:
linuxmint/cjs#135

I've fixed a few warnings, but some remain....

Type GITypeInfo of property XApp.StatusIconInterface::icon-name does not match type GITypeInfo of first argument of setter complete_scroll. Falling back to slow path
Type GITypeInfo of property XApp.StatusIconInterface::label does not match type GITypeInfo of first argument of setter complete_scroll. Falling back to slow path
Type GITypeInfo of property XApp.StatusIconInterface::tooltip-text does not match type GITypeInfo of first argument of setter complete_scroll. Falling back to slow path
...
...

These seem like false-positives, though - it's comparing unrelated elements. I think it's a bug in gobject-introspection (well, glib now)