Make used environment and configuration available

Make the used environment variables as well as the configuration
available as part of the qbs::Project API.

This allows creator to be more intelligent about when a reparse is
needed due to environment and/or configuration changes.

Change-Id: If6c7d5886db353137ddc346667690e3db97c0670
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
Initialize some more bools

Change-Id: I889eef047fd360452d77559777782c5c94a19ea0
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>