Refactoring and debugging of Jordan Wigner transform (Issue #67) (#82)

This PR fixes #67. Previously, the Jordan Wigner transform did not work correctly, in fact it generated
Hamiltonians with wrong coefficients or terms. This PR fixes that.

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Signed-off-by: kvmto <[email protected]>
Signed-off-by: Ben Howe <[email protected]>
Signed-off-by: Scott Thornton <[email protected]>
Co-authored-by: Ben Howe <[email protected]>
Co-authored-by: Alex McCaskey <[email protected]>
Co-authored-by: Scott Thornton <[email protected]>