Add path component matching to request testing

[Overcoat](https://github.com/Overcoat/Overcoat) implements service endpoint testing in a neat fashion:

`You don't need to specify the full path, and you can use * and ** to match any text or # to match only digits.`

`If you use * and #, they are strict path matchings, so the number of path components must be equal. The ** just matches any text and has no path components number limitation.`

| Match String | Path | Result |
| --- | --- | --- |
| statuses/* | statuses/user_timeline | Matched |
| statuses/# | statuses/user_timeline | Missed (wrong type, the path component after statuses should be dights only) |
| statuses/* | statuses/retweets/12345 | Missed (wrong number of path components, there should be only one path component after statuses) |
| statuses /\* /* | statuses/retweets/12345 | Matched |
| statuses/** | statuses/retweets/12345 | Matched |
| statuses/** | statuses/retweets/12345/extra | Matched (the number of path components doesn't matter) |
| statuses/retweets/* | statuses/retweets/12345 | Matched |
| statuses/retweets/# | statuses/retweets/12345 | Matched |

It'd be really neat if OHHTTPStubs had a method that implemented similar logic, rather than always having to manually work out this logic on every single test.