[ Issue 1353 ] Test case (works on maint).
[ Issue 1350 ] Fixed haddocumentation and added tests of cluster functions.
Merge branch 'maint-2.4.2'
[ Issue 1353 ] Test is broken on master (probably due to sharing bug).

* Agda normalizes too far in goal display.
* De Bruijn bug leads to unjustified error message.