Bump version number to 0.8.1
Bump version number to 0.8.1

FFroehlich/AMICI,AMICI-developer/AMICI,FFroehlich/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,FFroehlich/AMICI,FFroehlich/AMICI