Update README.md
fixed a bug that fails to find expansion for unitary_transformation(U, sy)
modified expansion_search with robert: moved the variable loop inside the expansion_search function
Merge pull request #7 from eunjongkim/expansion_search

fixed a bug that fails to find expansion for unitary_transformation(U, sy), U = exp(I*Omega*sp*sm*t)
clean up qutility.py
Merge branch 'master' of https://github.com/sympsi/sympsi