[blib2to3] Fixed a typo and removed an unused import. (#848)

blib2to3/pygram.py

@@ -9,7 +9,6 @@
 # Local imports
 from .pgen2 import token
 from .pgen2 import driver
-from . import pytree
 
 # The grammar file
 _GRAMMAR_FILE = os.path.join(os.path.dirname(__file__), "Grammar.txt")

blib2to3/pytree.py

@@ -335,7 +335,7 @@ class Leaf(Base):
     # Default values for instance variables
     _prefix = ""  # Whitespace and comments preceding this token in the input
     lineno = 0    # Line where this token starts in the input
-    column = 0    # Column where this token tarts in the input
+    column = 0    # Column where this token starts in the input
 
     def __init__(self, type, value,
                  context=None,