pdf: fix optimal dpi detection

The first 4 coefficients of the matrix must be taken into account,
since the image may be rotated...

git-svn-id: svn://svn.code.sf.net/p/mcomix/code@1073 ef8490bc-f317-4725-81ed-e95a9aca1bcf
archlinux: add directory
fix mcomixstarter.py python version
show archive name in status bar while loading
recursive archive: fix spurious errors

Filter-out directories when looking for sub-archives, so we don't error
out when trying to open them...
file handler: always save last read page

So books are always added to the library.