SP mapPotential_() returns sparse array of active indices

instead of dense array of 0/1 for each input position
change numbers in unittests for mapPotential
Merge branch 'master' into sparse_mapPotential
add debug statement
add SparseBinaryMatrix.rowFromSparse()
debug statement 2
fix unit test
Merge branch 'master' into sparse_mapPotential
Merge pull request #201 from breznak/sparse_mapPotential

Sparse map potential