stringdistmatrix was missing `p` when `ncores==1`

in stringdistmatrix
this line was missing the argument `p`:
  if (ncores==1){
     x <- sapply(b,do_dist,a,method,weight,maxDist, q, p)
   }
Merge pull request #7 from rsaporta/patch-1

stringdistmatrix is missing `p` when `ncores==1`