Merge branch 'master' of https://github.com/ahkab/ahkab into tests
Add options to calculate_poles()
BUGFIX: use lil matrices for J.
Use sparse matrices only for big (n>400) circuits by default
Merge branch 'master' of https://github.com/ahkab/ahkab into tests
TEST: add m-2m EKV ladder test.
Merge branch 'master' of https://github.com/ahkab/ahkab into py3
Merge branch 'tests' of https://github.com/ahkab/ahkab into py3