Qulacs

Updates
* SIMD optimization according to Intel AVX2 instructions (181, thanks to corryvrequan)
* Fix definition of “norm” (184, thanks to corryvrequan)

Bugfixes
* Bugfix about GPU index constant (180, thanks to corryvrequan)
* Bugfix of dense matrix gate in gpusim (182, thanks to puyokw)

Bugfixes

* Bugfix for GPU simulator
* Bugfix in get_norm() method, python setup scripts for windows, and matrix gates (thanks to corryvrequan)
* curand flag for windows(149, thanks to shukob and corryvrequan)
* Change ownership of data_cpp to avoid memory leaks in GPU simulator (thanks to corryvrequan)
* Bugfix in build script (thanks to Rogerluo and corryvrequan)

Bug fixes

* State sum and constant multiplication on QuantumStateGpu (163, thanks to puyokw)
* Bugfix on state norm (164, thanks to puyokw)

New features & Updates
* Two qubit depolarizing noise gate (148, thanks to corryvrequan)
* Show error message, return NULL ptr, and raise exception for invalid gate instantiation (158 and 159, thanks to kenjikun and corryvrequan)
* Add get_qubit_count function for python (153, thanks to yamamoto-takahiro and corryvrequan)

Bug fixes
* Bugfix in two qubit dense gate in C simulator (145, thanks to k-ishizaka and corryvrequan)
* Fix cmake script for GPU on ubuntu (149 and 150, thanks to shukob)
* Fix parametric quantum gates to be compatible with recently added `DensityMatrix` class (152, thanks to corryvrequan)
* Bugfix on gpu state load (154, thanks to corryvrequan and yoooopeeee)
* Fix a problem in CMake script which didn't work when path contains "./src/" (155, thanks to miyo and corryvrequan)
* Bugfix of freeing unreleased memory in sampling gpu (157, thanks to puyokw)
* Add gpu version of inner_product to python (160, thanks to puyokw)

This is a hot-fix release that fixes an issue on parametric gate (https://github.com/qulacs/qulacs/pull/140).

For those who have installed Qulacs 0.1.4, please update qulacs from PyPI (`$ pip install --upgrade qulacs`).

New features & Updates
- Add `DensityMatrix` class (131, thanks to corryvrequan)
- Add Dockerfile (129, thanks to yurisan)
- Add functions of cudaStream version in order to launch several kernels simultaneously (130, thanks to puyokw )
- Add 'get_name' method for `QuantumGateBase` class (135, thanks to yamamoto-takahiro)

Bug fixes
- Debug gpu version of transition_amplitude_multi_qubit_pauli_operator_Z_mask (130, thanks to puyokw )
- Bugfix for independent XZ noise (131, thanks to corryvrequan)
- Bugfix for parametric gate bugs in gpu state (138, thanks to corryvrequan)