Config: expose config rules parsing

Expose Config.parse_bool() and Config.parse_int() to parse text
according to git-config rules.

pygit2/config.py

@@ -223,6 +223,25 @@ class Config(object):
         err = C.git_config_add_file_ondisk(self._config, to_str(path), level, force)
         check_error(err)
 
+    #
+    # Methods to parse a string according to the git-config rules
+    #
+
+    @staticmethod
+    def parse_bool(text):
+        res = ffi.new('int *')
+        err = C.git_config_parse_bool(res, to_str(text))
+
+        return res[0] != 0
+
+    @staticmethod
+    def parse_int(text):
+        res = ffi.new('int64_t *')
+        err = C.git_config_parse_int64(res, to_str(text))
+        check_error(err)
+
+        return res[0]
+
     #
     # Static methods to get specialized version of the config
     #

test/test_config.py

@@ -179,5 +179,12 @@ class ConfigTest(utils.RepoTestCase):
         self.assertTrue('core.bare' in lst)
         self.assertTrue(lst['core.bare'])
 
+    def test_parsing(self):
+        self.assertTrue(Config.parse_bool("on"))
+        self.assertTrue(Config.parse_bool("1"))
+
+        self.assertEqual(5, Config.parse_int("5"))
+        self.assertEqual(1024, Config.parse_int("1k"))
+
 if __name__ == '__main__':
     unittest.main()