Add non-working demo for vector-valued custom integrals
Use custom defined jump() in vector custom integral demo
Handle tabulation of empty psi table for vector elements
Further hacking for tabulation of non-scalar empty psi_tables...
Small fix for computing value shape. Code generation for vector elements
is running now but offsets/indices etc need to be sorted out.
Rework extraction of used derivatives in psi_tables to also
include used components.
Work on extraction of basis functions and derivatives for vector elements
Bug fixes in tabulation of basis functions and derivatives in
custom integrals
Update reference data pointer to d2d295f6fb3c98323166c6345efb3dbe7fb2de42.
Cleanup and add working (as in code generation spitting something out)
example for mixed system (Stokes) for custom integral.
Small change in Stokes custom integral demo
Merge branch 'logg/topic-vector-custom-integral'
Update reference data pointer to c21597e1b1fd4d4666ed22cc76121b66c706c8a7.
Small fix in demo