Merge pull request #46 from RandomInsano/patch-1

Grammar fix

README.md

@@ -6,7 +6,7 @@ This allocator is used as the default Redox.
 
 ## A note on its state.
 
-It fully works, although it is somewhat slower than jemalloc, since it haven't
+It fully works, although it is somewhat slower than jemalloc, since it hasn't
 been optimized yet.
 
 I consider the state of the code quality very good.