Make all registry data members non-mutable

This pull request is another small step towards the multithreaded framework.  It eliminates the last three mutable data members from registries.  The Parentage, ProcessConfiguration, and ProcessHistory classes each contained a mutable cached hash id used for storage in a registry.  In the case of Parentage, the cached ID is simply removed, because it is not needed.  In the case of the other two classes, the cached ID is made non mutable.  The "id()" function remains const, because, while it still reads from the cache, it no longer fills the cache.  A new "set" function fills the cache when needed.
Also, in the case of Parentage, a non-const function with the same name as a const function is removed and replaced with other functions.
Also, "for" loops affected by this change are changed to C++11 range for loops.
This code has been fully tested with checkdeps -a.  All framework unit tests and relval matrix tests pass.