normalizedast: hide newTree from std/macros (#333)

Whatever Nim merged recently caused macros.newTree to have higher
precedence against newTree defined on NormNode within normalizedast.

As a workaround, don't import macros.newTree.

cps/normalizedast.nim

@@ -1,4 +1,4 @@
-import std/macros
+import std/macros except newTree
 import std/strformat
 from std/hashes import Hash, hash
 from std/sequtils import anyIt, toSeq