Remove b mode from files

This does not work well with python 3. Besides, most of these files are just there for unit tests,
so this is not so important

Author: iMichka

pygccxml/declarations/decl_printer.py

@@ -504,5 +504,5 @@ def dump_declarations(declarations, file_path):
 
     """
 
-    with open(file_path, "wb+") as f:
+    with open(file_path, "w+") as f:
         print_declarations(declarations, writer=f.write)

unittests/file_cache_tester.py

@@ -53,7 +53,7 @@ def test_update(self):
         # We wrote a //touch in the header file. Just replace the file with the
         # original content. The touched file would be sometimes commited by
         # error as it was modified.
-        with open(self.header, "wb") as new_header:
+        with open(self.header, "w") as new_header:
             new_header.write(content)
 
     def test_from_file(self):

unittests/project_reader_correctness_tester.py

@@ -41,10 +41,9 @@ def __test_correctness_impl(self, file_name):
             s = src_decls[0]
             p = prj_decls[0]
             bdir = autoconfig.build_directory
-            with open(os.path.join(bdir, file_name + '.sr.txt'), 'wb+') as sr:
+            with open(os.path.join(bdir, file_name + '.sr.txt'), 'w+') as sr:
                 with open(
-                        os.path.join(bdir, file_name + '.pr.txt'),
-                        'wb+') as pr:
+                        os.path.join(bdir, file_name + '.pr.txt'), 'w+') as pr:
 
                     declarations.print_declarations(
                         s, writer=lambda l: sr.write(l + os.linesep))