CaloTower fixes for Phase 2

This commit fixes a few CaloTower bugs for Phase 2 HCAL geometries:
1) Correctly interprets geometries where the entire HE has 5 degree ("single") phi segmentation, so the 10 degree ("double") segmentation doesn't start until HF.
2) Uses the CaloTower continuous ieta values in the constituents map for CaloTower DetIds (instead of the HCAL ieta values which may not be continuous in Phase 2 geometries).

I'm hoping this pull request can be accepted before the SLHC13 deadline tomorrow...