Throw Exception in QP Solver

[Woolfrey]

QP Solver should throw an exception when the start point x0 is outside the constraints. Currently it only returns the x0 and prints an error message to the console.

Since the start point is infeasible, the exception should be handled by the program which calls the solve() function.

[Woolfrey]

Completed, but also QPSolver is its own repository: https://github.com/Woolfrey/SimpleQPSolver