srcloc plugin: add src locs to handlers, also allow general comments.
tower-aadl: add handler comments to AADL output.
Don't try to add ivory-aadl
Merge remote-tracking branch 'origin/srcloc' into tower-9
tower-aadl: fix cabal file to no longer depend on ivory-backend-aadl

no longer exists but i bet it was hanging out in lee's sandbox. travis caught it