ttlogmerge: ignore afk/off/RETRO when working out which of two log lines has more content
ttlogmerge: add TODO
ttlogmerge: convert to make output filename optional (default: STDOUT)
beeminder.pl: move cache files to main directory
ttlogmerge.pl: improvements
ttlogmerge: better handle error lines in the log
beeminder.pl: Regenerate cache if cache file empty (facilitates syncing with Unison across multiple machines)
Merge branch 'ttlogmerge'

Conflicts:
	beeminder.pl