Update names for WalkNamespace callbacks to clarify usage.

Use of "preorder" and "postorder" was incorrect. The callbacks are
simply invoked during tree ascent and descent during the
depth-first walk.
iASL: Add some new requested features for the -so option.

Add support for Processor/Device/Scope/ThermalZone objects.
Emit offset of last nameseg for operators with namepath operands
ASLTS: Some additional fixes to support recent DerefOf behavior change.

Can no longer DerefOf on an uninitialized package element.