Make 'h' in thread leave thread

'h', the opposite of 'l' seems like the sane key to use to leave the
comment thread.
Avoid screen flickering

Use erase instead of clear to avoid screen flickering. clear will cause
curses to repaint entire window from scratch, which causes flickering.
Merge pull request #23 from omajid/h-to-leave-thread

Make 'h' in thread leave thread
Merge pull request #24 from omajid/no-flicker

Avoid screen flickering
Breaking out of comments now breaks out of all comments
Merge pull request #25 from Rubear/master

Breaking out of comments now breaks out of all comments
Selected comment stays selected after getting more posts and self posts are now displayed as first comment unless it's a link in which case the url is displayed
Merge pull request #26 from Rubear/master

Selected comment stays selected after getting more posts and self posts ...