Add more fixes for directory cache and python3

Author: iMichka

pygccxml/parser/directory_cache.py

@@ -379,13 +379,13 @@ def _create_config_signature(config):
         m = hashlib.sha1()
         m.update(config.working_directory.encode("utf-8"))
         for p in config.include_paths:
-            m.update(p)
+            m.update(p.encode("utf-8"))
         for p in config.define_symbols:
-            m.update(p)
+            m.update(p.encode("utf-8"))
         for p in config.undefine_symbols:
-            m.update(p)
+            m.update(p.encode("utf-8"))
         for p in config.cflags:
-            m.update(p)
+            m.update(p.encode("utf-8"))
         return m.digest()