Convert various archetypes to new use_archetype form, that requires id-codes.

Also remove unnecessary 'occurrences = 0' nodes, since they are now covered by other use_archteype nodes that redefine what was being prohibited.
Add new codes in terminology section as required.
Correct coding and use_archetype statement in Hematocrit archetype.
Move CBC archetype and template up 2 levels so it can have items that are other clinical statements, rather than just laboratory_tests, as is the case with Labroatory_panel, which it used to specialise.