checksysodesol method to check for solutions of system of odes

This PR contain checksysodesol method which checks for solutions given for system of ODEs. This also takes into account those equation where number of equation is not equal to number of functions as long as solutions for each functions is given.
I think this error should be a bit more detailed. I think you're trying to state that the number of solutions provided doesn't match the number of functions. Just state that instead. That way, it's clear why it's not sufficient.