Remove commas from parsed torrent file sizes before converting them into floats.

Tried running ``freeleech.py`` and got the exception below.

```
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/gevent/greenlet.py", line 327, in run
    result = self._run(*self.args, **self.kwargs)
  File "./freeleech.py", line 60, in getContent
    size += float(tmp[0]) * MB_TO_GB
ValueError: invalid literal for float(): 1,009.91
<Greenlet at 0x15c1cd0: getContent('http://what.cd/torrents.php?page=1&freetorrent=1', <urllib2.OpenerDirector instance at 0x161c3f8>)> failed with ValueError
```

Removing the commas in ``tmp[0]`` before the conversion into float fixes this.