Add support to pro2cmake to handle variable assignments via functions,
e.g: TARGET = $$qtTargetLibrary($$TARGET). The evalulation of the
functions happens during parsing and is very rudementary in nature.
Currently it only covers the qtTargetLibrary(), required for certain
projects, and quote(), required for passing unit tests.
If we run into any unhanlded function an exception will be thrown.
This patch also changes the TARGET property on Scope to expand the
value.
Change-Id: I678b7058067348a3972944bdba110f556cf22447
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Qt CMake Build Bot
