Streamline dependencies and build, de-duplicate IRI

[drsteve]

SCE adds new dependencies (GLOW) as well as duplicating current dependencies (IRI).
Ideally the SCE dependencies should all be in srcExternal and we should have no duplication. The IRI for GLOW/SCE also has its own input files that are duplicates of the IRI input files in the main input folder. This may require some work to streamline the build and ensure that all input files are moved into run directories correctly.

See also #92 and #93.