i believe your opponent would have been better off by capturing the bishop on move 46. ie.
46. Bh5+ Kxh5
47. g4+ hxg3 (en passant)
48. Rxh2 gxh2
And you would still be a pawn up and most probably would win but you opponent would have a much better fighting chance as your king would be away from the center passed pawn in order to capture his/her h-pawn and that way he could direct his king there. But thats just me.
I was playing in Live Chess(which has improved alot since the update), in an unrated game, so I allowed myself to go crazy, and here's the game: