EnvironmentRedirect base class for environment redirects

superclass: Object

Environment that redirects access (put) and assignment (at). 

*new(envir) create new redirect, if envir is given it is used.

envir return the source environment

envir_ replace the source environment

Overriding the following methods, one can redirect where objects go when they are assigned to 

the space: at, put, localPut, removeAt.

This is done for example in LazyEnvir and ProxySpace.

EnvironmentRedirect implements some of the 

interface of Environment, which it can replace where needed:

*push, *pop, push, pop, make, use, do, clear, keysValuesDo, keysValuesArrayDo,

findKeyForValue, sortedKeysValuesDo, choose, <>know, doesNotUnderstand

Networking:

EnvironmentRedirect and its subclasses can be used to dispatch assignment over a network.

To do this, a dispatch function can be supplied - see Public.