When the task text contains a url it could minify it automatically

It would be nice if it could minify urls contained in the task. Obviously, some people like to use `t` offline, so this could be a flag based feature (we would probably be hitting some API to get the minified url).

For example:

``` bash
$ t --minify-url Comment on PR: https://github.com/megacorp/proj/pull/5
$ t
4 - Comment on PR: https://bit.ly/234rkYC
```
