Preload updates to support QC GRT attachment

Conflicts:
	extern/ion-definitions
	ion/processes/bootstrap/ion_loader.py
Cleaned up precision mgmt
Adds some visibility limitation on lookup params
Fixes for pydap support
Updates ion-defs ref
Fixes type issue
Adds precision formatting to get_last_granule in DPMS
Finalizes QC and simulator support
Fixes test_global_range_lookup
Fixes test_row_values
Removed obsolete test
Merge pull request #981 from lukecampbell/qc

QC Work