moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

cranelift/codegen/meta-python/test_constant_hash.py

@@ -0,0 +1,8 @@
+from __future__ import absolute_import
+import doctest
+import constant_hash
+
+
+def load_tests(loader, tests, ignore):
+    tests.addTests(doctest.DocTestSuite(constant_hash))
+    return tests