Match Page permission descriptions to rules

Descriptions of what user can do with various Page rights
should talk about pages instead of categories.
RSS description message can now address single or multi-author setup

"each of your post" flows better when trimmed to "each post".

This change also frees it up for when blog is multi-author as it
is no longer confined to addressing one person, but for all posts
as a complete blog whole.
Update Google Webmasters link about rel=canonical
Merge pull request #105 from randomecho/page-rights-seed-description

Match Page permission descriptions to rules
Merge pull request #106 from randomecho/copyedit-seo-settings

RSS description message can now address single or multi-author setup
Fix a bug in the automated migration process. Under some undefined circumstances (reproduced on Debian wit Ruby ruby 1.9.2p136 but not on Mac OS 10.8 Ruby 1.9.3p194), administrator would be kicked out of the application because the sort_by{} would get confused where a sort is enough. Tested on both environments
Fixes typo behavior when trying to perform an unauthorized action within the admin. Instead of redirecting to the login, user is redirected to the dashboard. Fixes #104
Remove the Rights model.

A long, long time ago, I wanted Typo permission systems to be as flexible as possible (and as user friendly as possible). My idea was to make the various profiles editable with a set of rights, everything within a fancy interface.

I started to push some things, then completely forgot about it. As this makes our permission system way more complicated than it should be, without a real interest, I'm now removing it all.

See #79 for more information.