generic proxy wrapper type for Python

 mxProxy is an extension package that provides a new type that is
 suitable to implement Bastion like features without the need to use
 restricted execution environments.
 .
 Given that current Python versions no longer support Bastion or rexec
 as secure sand-box execution models, mxProxy fills an important
 gap. It also gives the programmer more control over how and to what
 extent access should be controlled or not.