ISO 9660 Boot Record and Primary Volume signatures, ref: http://wiki.…

Create extraction dir if it does not exists

Removed excessive size field validation for LZMA signatures; their compression is already validated, which is a better metric anyway.

Zip footer signature accurately reflects its size

Added a KGB archive signature.

adding MPEG transport stream signatures to magic/animations

Add signatures for qnx6fs & qnx ifs

several firmware magics

Update kwarg processing to ensure modules don't receive a mutable reference to defaults

Update kwarg processing to ensure modules don't receive a mutable reference to a class variable default. Fixes #207, also the Signature Modulemodule was leaking memory.

Ignore dotfiles when discovering magic files

Some programs (which?) might create temporary files like `~name` or
`_name`, but maybe there are people who actually rely on names like
`_name`. Let's restrict the filter to just dotfiles for now.

Fix custom output directory for extracted files