Fixed segfault on postProcess sort
Improved postprocess performance by pruning the characterset before sending to the recursive sort.
This uses the "topN" value to remove lower scoring characters that couldn't possibly show up in the topN results
Merge https://github.com/vebers/openalpr into develop
Updated postprocess permutation calculation to handle corner cases (topn = 1 and permutations == topn)
Print all the letters (debug output) in postprocess before pruning them