Lightsim2grid

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- [FIXED] a bug for static generator (wrong signed convention were used in some part of the c++ code). This has
no impact at all for provided grid2op environments.
- [FIXED] An issue where the backend could get "stuck" in a wrong state because of the way the Vinit was computed (see
`Issue 30 <https://github.com/Grid2Op/lightsim2grid/issues/30>`_)
- [ADDED] experimental support for the `NICSLU` linear solver (requires a proper license and library, see
https://github.com/chenxm1986/nicslu for more information. Support does not include multi threaded at the moment).
- [IMPROVED] minor performance improvements for the solvers based on Newton Raphson (faster filling of the Jacobian
matrix after the first iteration)

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- [FIXED] minor issues in the benchmark (some time measurments were wrong)
- [ADDED] lightsim2grid package now can be distributed on pypi
- [ADDED] compilation of SuiteSparse using cmake
- [ADDED] compatibility with the KLU linear solver on windows based systems.
- [IMPROVED] the package should now be available on pypi

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- [FIXED] `GridModel` now properly throw "out_of_range" exception when trying to change the bus of non existing
elements
- [FIXED] wrong units were displayed for the iterators for lines and transformers.
- [ADDED] now able to retrieve the powerlines parameters python side.
- [IMPROVED] more explicit error messages when the building of the `Ybus` matrix fails.
- [IMPROVED] now the solver is not reset when using the `backend._grid.check_solution`
- [IMPROVED] upgrade SuiteSparse to version `v5.10.1`
- [IMPROVED] upgrade eigen to version `3.4-rc1`

-------------------
- [FIXED] yet another compilation issue with clang (see
`Issue 22 <https://github.com/Grid2Op/lightsim2grid/issues/22>`_)
- [ADDED] circleci to check compilation for gcc
- [ADDED] circleci to check compilation for clang
- [ADDED] circleci to check compilation for msvc
- [ADDED] function to read the voltage angle from the backend
- [ADDED] compatibility with grid2op 1.5.0 (up to an issue with the storage units)

-------------------
- [FIXED] a compilation issue on macos
- [FIXED] a compilation issue on windows (missing import of vector in `DataConverter.h`)
- [FIXED] an import issue (with `lightsim2grid.SolverType`)
- [FIXED] a bug that lead to the wrong computation of the ratio of the trafo when the tap on hv side.
- [FIXED] wrong timing was measured in the "solver powerflow time" of pandapower in the benchmarks
- [FIXED] a broken handling of shunt modification (wrong bus was assigned)
- [FIXED] an issue in `LightSimBackend.copy` that prevent the copied environment from being reset.
- [FIXED] errors are now raised when pandapower grid cannot be converted in lightsim2grid (*eg.* when
unsupported elements are present)
- [ADDED] a variant of the Gauss Seidel method which does the update in a "synchronous" fashion
- [ADDED] a function that, given a complex vector is able to check kicchoff's law violation.
- [ADDED] Support for phase shifter (modeled as trafo with an extra parameter `shift`)
- [ADDED] Experimental support for `sn_mva` pandapower parameter.
- [UPDATED] github issue template
- [IMPROVED] warnings are issued when some of the pandapowergrid attributes have been automatically replaced
when converting to / from pandapower

---------------------
- [ADDED] the Gauss Seidel method for AC powerflow is now available
- [ADDED] possibility to change easily the solver types from python side