Solve the following mathematical recurrence $($your answer should provide a closed form expression for T$($n$).)$:

$T(n)=\{\begin{array}{cc}1,& n=1\\ 2T(\frac{n}{2})+n,& n>1\text{a}\text{n}\text{d}nis\text{a}\text{p}\text{o}\text{w}\text{e}\text{r}of& 2\end{array}$