Use relative imports in compiler package now that it is required. (Should this…

Use relative imports in compiler package now that it is required.  (Should this go into 2.5 or should we do compiler.XXX?)

Lib/compiler/__init__.py

@@ -21,6 +21,6 @@ compileFile(filename)
     Generates a .pyc file by compiling filename.
 """
 
-from transformer import parse, parseFile
-from visitor import walk
-from pycodegen import compile, compileFile
+from .transformer import parse, parseFile
+from .visitor import walk
+from .pycodegen import compile, compileFile