Fix merge users command.

Sometimes user records cannot be merged because the result
is an identical record. Manual transactions are used to
only select the ones that work.
quick css fix for user card
added documentation to migrate from mysql to postgresql
fixed feed issues with unescaped html
fixed line height for user card, and reverted the last change
Merge branch 'master' into usercardfix
removed strip_tags from the rss feed definition
Merged fix by Paul Backhouse for the merge_users command
fixed the management command init_postgresql_full_text_search
fixed the ask button on the settings page
edited the readme file
fixed issue with question flagging
added files for the Vietnamese locale
updated doc
added Vietnamese translators to the contributors list
Merge branch 'adolfo'
added link to the mysql to postgres migration
small change in the feed generation
Merge branch 'adolfo'
fixed css for the user info box on the posts