Remove documentation references to "pg_dumps/development-image.sql".

There is no such file. Seeding is accomplised via the rake tasks as of
9ab743f351e612830a27afaab8e9b3ddd59da9e2.
Fix pasting into the subject field in Firefox.
FIX: categories with non-ascii names will have broken next page urls
Merge pull request #2168 from zsombor/master

Remove documentation references to "pg_dumps/development-image.sql".
Merge pull request #2172 from vikhyat/firefox-paste-image

Fix pasting into the subject field in Firefox