Revert "Revert "Merge branch 'feature/7415_vision_performance' into develop""

This reverts commit a7024dcaeebd7cda35aaa8e74aabdd0c22897c3d.
Revert "Revert "Merge branch 'feature/7415_vision_performance' into develop""

This reverts commit 625ad59c769ed3fe89d5f04a67c12c95c670b5d3.
Revert "Revert "Merge branch 'feature/7415_vision_performance' into develop""

This reverts commit f8d4cb464a18c17b03a7f84e5d2b6ebd6e2a827f.

Re #7415

Conflicts:

	Code/Mantid/Framework/DataHandling/src/LoadEventNexus.cpp