Extensively modified how ThreadImplementations work and
refactored AadlModelParser into a more sane organization.
AadlModelParser should probably be refactored further into
separate files, but at least it is comprehensible now.
MWW: finished refactoring the phase I stuff: threads can have multiple
ISRs as input event ports and FLIH and SLIH handlers are explicitly
separated (and under the control of the component writer).
MWW: finished refactoring the domain model; now it is quite clean;
added support for ISRs as ports and active and passive threads.
Active and passive threads are not yet hooked up into the code
generator, but this is coming shortly.
Merge branch 'develop' of https://github.com/smaccm/smaccm into develop

Conflicts:
	models/GPCA/packages/GPCA_SW.aadl

Two versions of the file that did the same thing: commented out the
"canary" property.  Chose one of the versions.