Insert command/separator before selected item in command editor.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@859 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Add note that comicthumb isn't actively maintained.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@860 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Begin work on fast-forward/backward key combo.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@861 ef8490bc-f317-4725-81ed-e95a9aca1bcf
Shift+NextPage/PreviousPage will advance/go back by 10 pages.

git-svn-id: svn+ssh://svn.code.sf.net/p/mcomix/code@862 ef8490bc-f317-4725-81ed-e95a9aca1bcf