fix parsing of power functions to actually include decimal numbers
fix parsing of power functions to actually include decimal numbers

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