Fix caching in tokenizer

spacy/tokenizer.pyx

@@ -1,4 +1,5 @@
 # cython: embedsignature=True
+# cython: profile=True
 # coding: utf8
 from __future__ import unicode_literals
 
@@ -268,7 +269,7 @@ cdef class Tokenizer:
                           int has_special, int n) except -1:
         cdef int i
         for i in range(n):
-            if tokens[i].lex.id == 0:
+            if self.vocab._by_hash.get(tokens[i].lex.orth) == NULL:
                 return 0
         # See https://github.com/explosion/spaCy/issues/1250
         if has_special: