[spaces.discontinuouslagrange.fem] add missing compute_pattern method
[spaces.discontinuouslagrange.pdelab] use discontinuous space
[tests.spaces_dg] add maps_correctly test
[tests.spaces] silence warnings
[spaces.discontinuouslagrange.pdelab] make PdelabBased pass tests
[tests.spaces_dg] fix P1Q1_Discontinuous_Lagrange test, clean up space definitions