Changelog for v 0.11

Version 0.11 represent the culmination of four months of efforts.

Features added:

• Add Pole-Zero (.pz) analysis.
• Add sparse matrix support and LU factorization with SuperLU.
• AC solutions data is returned as complex floats.
• The brute-force PSS algo is now known as 'brute-force'.

Ahkab also got considerably faster in DC/OP/TRAN/PSS analyses.

A PY3 version passing the whole test suite is available in the
repository.

Changes from contributors and pull requests merged:

None.

Bugs fixed, short list:

• BUGFIX: Remove print_circuit(), use print(circuit).
• BUGFIX: EKV devices now match the usual constructor.
• BUGFIX: do not attempt to print conv. details if sing. MNA
• BUGFIX: Use ndarrays (almost) everywhere, drop mats.
• BUGFIX: Don't crash if a plot label is not found.
• BUGFIX: CMIN-related crash.
• BUGFIX: Remove hack for now closed bug in sympy.
• BUGFIX: Reset sim options before skipping a test.