Get rid of variableEnvironment

Get rid of variableEnvironment

Found out that the variableEnv is only required
for two use cases: To expose the exception in the
catch statement, and to create temporary
environments for the with() statment. Both can be
better handled differently and don't require the
overhead of two environments.

Change-Id: I149e1fd7bdfc3267544b141b6f94e46e42cf641b
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>