[Bug] Weird warning & InstaLooter won't download all posts

Noticed a few days ago that I sometimes get a warning saying instalooter could not find a page.

` WARNING - Could not find page of user: justinbieber`

The warning comes similarly like when instaLooter checks for new posts and doesn't find any. This is what I run:
`instaLooter justinbieber C:\Users\AZ\Desktop\Insta\JB --get-videos -T "{username}.{datetime}.{id}" -N -m`
Sometimes the message appears even when instalooter continues downloading.

I tried to download different profiles to test things around, and I noticed that instalooter didn't download all posts. For example, I ran:

`C:\Users\AZ\>instaLooter alexiaelkaim D:\Backup\Pictures\Instagram\Profiles\alexiaelkaim --get-videos -T "{username}.{datetime}.{id}" -N -m` , downloading a profile with 1108 posts. Now, instagram website doesn't count the additional posts in multiposts, so it's a few more pictures than that (as instaLooter also downloads multiposts".) I look at my folder, and I have 1116 pictures. The catch is that a week ago I downloaded the same profile, and in that folder I have 1235. Maybe instagram changed something and not all posts are downloaded now?

I also get another warning. I have gotten the same warning since I used instaLooter, but rarely. The posts did download properly so I didn't think of it at all, but now whenever I use instaLooter, the warning always pops up.

```
C:\Users\AZ\>instaLooter alexiaelkaim D:\Backup\Pictures\Instagram\Profiles\alexiaelkaim --get-videos -T "{username}.{datetime}.{id}" -N -m
Loading pages | 25%(12 of 47)|### |Elapsed Time: 0:00:08 |ETA: 0:00:24Exception in thread Thread-15:
Traceback (most recent call last):
File "c:\python27\lib\threading.py", line 801, in __bootstrap_inner
self.run()
File "c:\python27\lib\site-packages\instaLooter\worker.py", line 65, in run
self._download_video(media)
File "c:\python27\lib\site-packages\instaLooter\worker.py", line 149, in _download_video
self._dl(video_url, video_name)
File "c:\python27\lib\site-packages\instaLooter\worker.py", line 158, in _dl
with contextlib.closing(self.session.get(source)) as res:
File "c:\python27\lib\site-packages\requests\sessions.py", line 515, in get
return self.request('GET', url, **kwargs)
File "c:\python27\lib\site-packages\requests\sessions.py", line 502, in request
resp = self.send(prep, **send_kwargs)
File "c:\python27\lib\site-packages\requests\sessions.py", line 652, in send
r.content
File "c:\python27\lib\site-packages\requests\models.py", line 825, in content
self._content = bytes().join(self.iter_content(CONTENT_CHUNK_SIZE)) or bytes()
File "c:\python27\lib\site-packages\requests\models.py", line 750, in generate
raise ChunkedEncodingError(e)
ChunkedEncodingError: ("Connection broken: error(10054, 'An existing connection was forcibly closed by the remote host')", error(10054, 'An existing connection was forcibly closed by the remote host'))
```