[operators.basic] bugfixes
[parameters.spaces] bugfix
[la.gram_schmidt] bugfix
[la.listvectorarray] bugfix
[operators.ei] bugfix
[domaindescriptions] add missing __ne__ method to BoundaryType
add some __repr__ methods to prettify sphinx documentation
[operators.basic] fix typos
[operators.basic] bugfix
[docs] fix typo
[operators.basic] allow linear NumpyGenericOperators
[discretizers.advection] allow parametric initial_data
[docs] update/add documentation
[core] disable_logging no longer unlocks the class

which would delete its sid in case of an immutable class!
[tests] fix logger test
[grids] use float_cmp instead of np.isclose in flatten_grid
[operators.fv] use diag_matrix instead of diags for compatibility with older SciPy versions
[tools] remove unnecessary future imports in pyx files

to be compatible with older Cython versions
[demos] remove obsolete 'reductor' parameter in thermalblock demo
[README] small update