Add %_live%, %_cover% etc. for work relationships.
Add NEWS
Switch variable names and add ~workrelationship

which mimics the work relationship statement on the MB web site e.g.
`{live} {medley:medley including a} {partial} {instrumental} {cover}
recording of`
Handle i18n differently ...

... so that work relationship text can be translated as a phrase and not
as individual words.
Remove ~workrelationship stuff.
Merge pull request #285 from Sophist-UK/sophist_add_work_relationship_variables

Add %_performance_live%, %_performance_cover% etc. for work relationships.