score: Clarify CPU port alignment requirements
score: Fix workspace size estimate
score: Fix POSIX threads size estimate

The POSIX threads are separate objects.  Account for the object
administration overhead.
score: Delete _Thread_Maximum_extensions

Use the Configuration instead.
score: Delete _Thread_Ticks_per_timeslice

Use the Configuration instead.
score: Lazy key value pair allocation
sptests/spwatchdog: Fix for short enums
tmtests/tm21: Fix configuration
score: Use proper protection
psxtests/psxkey02: Test for proper error case
score: Fix for empty heap
sptests/sp68: Fix configuration