copy 2.7 magic numbers for historical interest

Lib/importlib/_bootstrap.py

@@ -351,6 +351,12 @@ Known values:
     Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)
     Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
     Python 2.6a1: 62161 (WITH_CLEANUP optimization)
+    Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND)
+    Python 2.7a0: 62181 (optimize conditional branches:
+                         introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
+    Python 2.7a0  62191 (introduce SETUP_WITH)
+    Python 2.7a0  62201 (introduce BUILD_SET)
+    Python 2.7a0  62211 (introduce MAP_ADD and SET_ADD)
     Python 3000:   3000
                    3010 (removed UNARY_CONVERT)
                    3020 (added BUILD_SET)