Fix grammar in README.md (#330)
Fix grammar in README.md (#330)


RoaringBitmap/RoaringBitmap,lemire/RoaringBitmap,RoaringBitmap/RoaringBitmap,lemire/RoaringBitmap,lemire/RoaringBitmap,RoaringBitmap/RoaringBitmap,lemire/RoaringBitmap,RoaringBitmap/RoaringBitmap