RF+TST: update doctest and code to return column vector versions of .a.{s,f}.dim.values
MRG: merge from _tent/clust
MRG: merge from _tent/clust
MRG: from _tent/clust
ENH+TST+RF: remove hdr_ft struct from synthetic dataset and cartesian_dim_transer doctest
NF: MEEG baseline correction