Documentation is unclear about change of basis

[eltrompetero]

User contacted me about using {0,1} basis with the Pseudo solver. Was unable to make it work. In line 1277 in v1.0.3, the Pseudo._solve_ising() method assumes that all given data is in {-1,1} basis and convert it to the {0,1} basis.

Documentation could be clearer about which bases are allowed.

Code could be updated to permit choice of basis when instantiating solvers.

[eltrompetero]

Default basis for Ising model is now {-1,1}. Usage guide was updated for this convention. There is almost no difference in choice of basis for speed now in Enumerate approaches, which was one of the main reasons for basis choice in the past.