Fix printf coverity errors in OPJFile.cpp

Refactor groupdetectors

Allow overwriting members of a WorkspaceGroup when setting output properties to the same workspace name

Fix normalization of atoms for compounds

Coverity issue in MDFDatasetPlotData.cpp

Remove old abs. correction code

We may as wel make sure to cover *all* the syntax in the doc test, to
ensure it all works.

The error is reproduced in the master branch, and absent in the issue branch

Just for file changes and not commits at the moment.

Fix IDR rebin default option

Display error bars in multi-data set fitting interface.

Added forward only headers for common workspaces.

Add txt extension for mask file browser