Utilities: Validate full RSDP header

Implement proper RSDP validation in AcpiUtReadTable(). Prevents a segmentation
fault that can occur if a user passes the wrong file to iasl.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Namespace: Properly null terminate objects detached from a namespace node

Fixes a bug exposed by commit 6af53b030395bb6bfa7a36812c41e9557a0bb003 where the
failure to null terminate a detached object led to the creation of a circular
linked list (and infinite looping) when the object is reattached.

Reported in acpica bugzilla #1063

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
AcpiExec: Add support to test attach/delete root node objects.

This change attaches two objects to the root node to test both
the attach and the actual object deletion upon ACPICA termination.

06/10/14: Patched reapplied after fixing inifinite loop error it
exposed when it was first applied. Dave Box