Support for an initial before_attribute in stream_generator

[c0d3rman]

Adds a continue_after_id parameter to the stream_generator function so that an initial value for before_attribute can be set.

Example use case: a script wants to process all new comments from a sub since the last time it's been run. It keeps the fullname of the last comment it saw on its previous run and wants to stream all comments starting from the one after that. It can do:

for comment in reddit.sub.stream.comments(continue_after_id=last_seen_fullname):
    # Do things...

[LilSpazJoekp]

Looks good except for a few concerns.

Could you also add an entry in CHANGES.rst?

[c0d3rman]

For CHANGES.rst, should I increment the version number? (And if so do I need to do that elsewhere as well?) Or should I put it in Unreleased?

[LilSpazJoekp]

Put it in unreleased under the **Added** header.

[c0d3rman]

Requested changes have been made.

[LilSpazJoekp]

Looks great. I just have a final couple of comments.

[LilSpazJoekp]

Merged in! 🎉Thank you!

[c0d3rman]

Thanks for all your help!

[c0d3rman]

By the way, question: what's the release schedule of PRAW like? I want to use this in a project of mine but not sure if to just wait or to hack around it in the meantime

[LilSpazJoekp]

There isn't really a release schedule. However, you can do pip install --upgrade https://github.com/praw-dev/praw/archive/master.zip to install the dev version.