Handle in pyfaust expressions like F[[1,2,3],] (equiv.to F[[1,2,3],:]) and fix...

Handle in pyfaust expressions like F[[1,2,3],] (equiv.to F[[1,2,3],:]) and fix a bug on fancy indexing-after-transpose operation.

FF.rand(4, 32).T[[1,2,3],].shape
was returning: (32,3) instead of (3,32).