Added explicit list of mutators to PIT config and increased number of threads
Added explicit list of mutators to PIT config and increased number of threads

alenkacz/stubby4j,jasonchaffee/stubby4j,azagniotov/stubby4j,azagniotov/stubby4j,jasonchaffee/stubby4j,azagniotov/stubby4j,azagniotov/stubby4j,alenkacz/stubby4j,jasonchaffee/stubby4j,alenkacz/stubby4j