Added several new thresholds to pars to control when matrices and submatrices are
considered dense/sparse.
Added parallel A1 structure to hold dense and sparse components of A separately.
Modified getada.m and Amul.m to use the new representation.
Removed unused threshold value from pars
Modified getsymbada to check for sparsity of the various matrices that it uses prior
to using them in multiplication, and make full if advantageous.