File-Open dialog does not sort files when directory is selected. [bugs:#47]

When a directory is opened using the File->Open dialog, the contents of said
directory are opened in operating system order, ignoring any sorting
preferences the user might have selected.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@835 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Mention sorting bugfix in ChangeLog.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@836 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Only remember last browsed directory if 'store recent file info' is True.

This closes [bugs:#46].

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@837 ef8490bc-f317-4725-81ed-e95a9aca1bcf