Move stuff that keeps track of playcount, restartpos, etc to playinfo.[ch]
Transfer playcount, restartposition and lastplay to kvstore.db

This used to reside in meta.db but I'd rather like to keep this
in the kvstore. Much simples and it will be a lot easier to split
out this for storing into xattr in filesystems instead

Note: This issues a non-backwards-compatible db changes so any
previous versions of showtime will not be able to read the metadata
database after this upgrade
Split Makefile into two parts to avoid building sub targets in parlallel
metadb: Get rid of 'metadataversion' from item table
prop: Improve debug output
prop: Fix a recent regression causing symlinks to break (again)

Fixes #1967