Removed mention of 0.6 prereleases from README
Removed mention of 0.6 prereleases from README

JoaoRodrigues/freesasa,JoaoRodrigues/freesasa,JoaoRodrigues/freesasa,mittinatten/freesasa,mittinatten/freesasa,JoaoRodrigues/freesasa,mittinatten/freesasa,mittinatten/freesasa