In rectangle ABCD, AD \equal{} 1, P is on AB, and DB and DP trisect ∠ADC. What is the perimeter of △BDP?
[asy]unitsize(2cm);
defaultpen(linewidth(.8pt));
dotfactor=4;pair D=(0,0), C=(sqrt(3),0), B=(sqrt(3),1), A=(0,1), P=(sqrt(3)/3,1);
pair[] dotted={A,B,C,D,P};draw(A--B--C--D--cycle);
draw(B--D--P);
dot(dotted);
label("A",A,NW);
label("B",B,NE);
label("C",C,SE);
label("D",D,SW);
label("P",P,N);[/asy] (A)\ 3 \plus{} \frac {\sqrt3}{3} \qquad(B)\ 2 \plus{} \frac {4\sqrt3}{3}\qquad(C)\ 2 \plus{} 2\sqrt2\qquad(D)\ \frac {3 \plus{} 3\sqrt5}{2} \qquad(E)\ 2 \plus{} \frac {5\sqrt3}{3} geometryrectangleperimetertrigonometry