added sum lin ops
started integrating new coefficient system
flattened multiplication
added function to convert lin ops to matrix blocks
added op to matrix func
basic problems work
last hurrah for flattened repr
moving towards expression tree
got basics working
got norm_inf, norm1, and norm2 working
starting transpose, finished square, norm2, index
added transpose
added sum_entries, working on index
fixed index
uncommented all problem tests
minor changes
Fixed bug where variables multiplied by zero ignored
converted geo_mean, log, all norms, max, min, sqrt
converted log_det
converted all atoms