In Calibre, there was decided to keep the fonts information inside the
configuration directory. While scanned fonts information is actually a
cache, I would keep it there. This commit is making that happen.
Also removed XMLConfig in favor of JSONConfig class, since XMLConfig is
not used at all.
There was (and perhaps it exists in other modules, need to check) a bad
habit of importing objects out of module A into B just to be able of
import those object from module B. In this case there was import from
module config_base into module config. This commit fix this.
Here is the first batch of modules, which are needed for converting
several formats to LRF. Some of the logic has been change, more cleanups
will follow.
