Johan Löfberg

Refactor work on #634

https://github.com/yalmip/YALMIP/blob/07caec843c9ba6946417f44b0f906fecbee680a1/%40sdpvar/floor.m#L23 same in ceil etc

`sdpvar x1 x2; Con=[x1^3+x2^3+x1^2*x2^2==22.875,x1+x2>=3]; optimize(Con,x1+x2,sdpsettings('solver','penlab')) check(Con)`

Sometimes we might be interested n seeing exactly what e.g. fmincon finds on a nonconvex model Requires #602 to be implemented

Simply use yalmip2quadprog

``` yalmip('clear') Pg_un=sdpvar(3,1,'full'); W=[0