Change type of row and collumn values to size_t
Change type of row and collumn values to size_t

Previously it was 'int' type.

narekgharibyan/keyvi,cliqz-oss/keyvi,cliqz-oss/keyvi,cliqz/keyvi,narekgharibyan/keyvi,cliqz/keyvi,cliqz-oss/keyvi,cliqz/keyvi,narekgharibyan/keyvi,cliqz/keyvi,narekgharibyan/keyvi,cliqz-oss/keyvi