Signed-off-by: Unknwon <u@gogs.io>

If the host setting looks like a unix socket (leading by char '/'), will use unix(host) as connection string

cmd/web.go: check version after load config

- routers: use new binding convention to simplify code
- templates: able to set HTTP port number in install page

A new struct is created named EmailAddress that contains alternative
email addresses for users. Also the email related methods; IsEmailUsed
and GetUserByEmail are updated.

DeleteUser deletes the extra email addresses and DeleteInactivateUsers
also deletes inactive accounts. This could be factored out, but should
do it for now.