Every mime related function in main __init__.py has a flag check for the
check if initialization has already done. This is nonsense, since it
should be done implicitly early on the converter is starting.
This commit straight the things out, and initialization is done in cli
module.
Also, function guess_type was removed, since it's just a proxy for
mimetypes.guess_type function.
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.
