Bump version to 0.3.0 and add alpha version disclaimer (quantumlib#317)

* bump version to 0.3.0

* add a suffix

* remove a

* add alpha disclaimer from readme

freeze cirq and openfermion requirements (quantumlib#275)

* freeze cirq and openfermion requirements

* add .1*

Cut release

Bump version to 0.1.0alpha (quantumlib#204)