Added cd_mkdir rule

This fixes #50 and #98.

```bash
$ cd foo/bar/baz
cd: foo: No such file or directory
$ fuck
mkdir -p foo/bar/baz && cd foo/bar/baz
```

Added matchers for both Bash and sh error messages. Depending on your
default shell, the messages might be slightly different.

tests/rules/test_cd_mkdir.py

@@ -0,0 +1,19 @@
+from mock import Mock
+from thefuck.rules.cd_mkdir import match, get_new_command
+
+
+def test_match():
+    assert match(Mock(script='cd foo', stderr='cd: foo: No such file or directory'),
+                 None)
+    assert match(Mock(script='cd foo/bar/baz', stderr='cd: foo: No such file or directory'),
+                 None)
+    assert match(Mock(script='cd foo/bar/baz', stderr='cd: can\'t cd to foo/bar/baz'),
+                 None)
+    assert not match(Mock(script='cd foo',
+                          stderr=''), None)
+    assert not match(Mock(script='', stderr=''), None)
+
+
+def test_get_new_command():
+    assert get_new_command(Mock(script='cd foo'), None) == 'mkdir -p foo && cd foo'
+    assert get_new_command(Mock(script='cd foo/bar/baz'), None) == 'mkdir -p foo/bar/baz && cd foo/bar/baz'