Handle new CEST data correctly
Summary:
Modify parsing for different "ASCCONV BEGIN"
New data does not mark the relevant section simply with
"# ASCCONV BEGIN #" but with something like
"### ASCCONV BEGIN object=MrProtDataImpl@MrProtocolData version=51130001 ..."
so the parsing needs check for different strings.
Replace tab ("\t") in new CEST image data files
Test Plan: manual testing
Reviewers: floca
Reviewed By: floca
Subscribers: floca, kalali
Maniphest Tasks: T28958
Differential Revision: https://phabricator.mitk.org/D591