Builds the A* matrix
buildAstar(foinew, ldfnew, grainsize, debug)numeric matrix representing the file of interest
numeric matrix representing the linking data file
integer determining minimum grain size for parallisation
Boolean indicating whether to output additional debugging information
buildAstar takes a matrix representing the file of interest and
a matrix representing the linking data file and creates a matrix that
can then be used to generating linking scores. Reporting frequency as this
occurs can be specified via the nreport option. This is implemented in C++
to provide a speed increase over implementing it directly in the R equivalent.