creddit: libreddit: Various fixes and clean-ups

This pull-request is a collection of patches fixing some small issues. I put them together since the commits are still separate and they're not really worth 3 separate pull-requests.

The first patch modifies ./run.sh so that any parameters passed to it are directly passed on to creddit when it is run.

The second patch fixes a small printing issue with the screens. When you have a Link or Comment open, the screen doesn't always get cleared and remnants can be left behind, this simply forces the screen to be cleared before the new Link or Comment text is drawn.

The third patch moves the Reddit.com related strings into global.h so it's easier to see what parts of the API we're using and which link's are being used for what (And if anything changes on Reddit's side, updating our links will be easier to do.)