Handle Connection Errors

Issue Description

If running collection for a historical period, often the connection is dropped with timeout errors for me. I’ve tried on my local machine and a server which is always on. Some simple error handling and requesting the same item (comment/post) again would be good.

Paste of code since GitHub formatted it poorly: https://pastebin.com/pNUpgJXL

Errors raised:

raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value) urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='www.reddit.com', port=443): Read timed out. (read timeout=16.0)

Followed by

raise ReadTimeout(e, request=request) requests.exceptions.ReadTimeout: HTTPSConnectionPool(host='www.reddit.com', port=443): Read timed out. (read timeout=16.0)

followed by

raise RequestException(exc, args, kwargs) prawcore.exceptions.RequestException: error with request HTTPSConnectionPool(host='www.reddit.com', port=443): Read timed out. (read timeout=16.0)

System Information

PRAW Version: 5.3.0

Python Version: 3.6.3 Operating System: OS X 10.13 || Ubuntu 16.04

[jarhill0]

I believe https://github.com/praw-dev/prawcore/pull/64 closes this.

[bboe]

For future reference you can triple quote the block like:

```
data
```