Genie:  Eradicate use of IOPtr typedef
mac-sys-utils:  Add default_thread_stack_size()
Genie:  Use mac::sys::default_thread_stack_size()
mac-sys-utils:  Add temp_free_mem()
Genie:  Use mac::sys::temp_free_mem()
mac-sys-utils:  Add free_mem()
mac-sys-utils:  Add heap_size()
Genie:  Use mac::sys routines in /sys/app handlers
Merge branch 'mac-sys'