Number incorrectly parsed as both resolution and episode number

[cvium]

On the latest 2.1.4 installed from pip, a number corresponding to a common resolution format is parsed as both episode and resolution.

I would expect it to be parsed as one or the other, not both.

(py3) ~$ guessit --version
+-------------------------------------------------------+
+                   GuessIt 2.1.4                       +
+-------------------------------------------------------+
+                   Rebulk 0.9.0                        +
+-------------------------------------------------------+
|      Please report any bug or feature request at      |
|     https://github.com/guessit-io/guessit/issues.     |
+-------------------------------------------------------+
(py3) ~$ guessit "One Piece - 720"
For: One Piece - 720
GuessIt found: {
    "title": "One Piece",
    "season": 7,
    "screen_size": "720p",
    "episode": 20,
    "type": "episode"
}

This is also present in the 3.0 dev branch.