* Do not create summary case group twice
* Fix memory leak of objects contained in childArrayFields
Use deleteAllChildObjects to delete objects instead of clear()
Rename collection function clear() -> deleteAllChildObjects
* Early exit for empty path
* Reduce redundant calls to refreshMetaData
HDF5 must be compiled with special options to support multithreading. Disable file object multithreading for HDF5. Some vector types are not supported, as the support in opm-common reader is not complete (region, region_to_region, ...).