The button appears when a file is viewed in a branch or a tag. It points
to a URL containing the branch's (or tag's) current commit id so that
it'll always point to the same content.

Signed-off-by: Dmitry Yu Okunev <dyokunev@ut.mephi.ru>

This reverts commit c226e92284c7b4b405352814155dd5da3458e029, reversing
changes made to 80b23854bc.

- update some locale files

- modules/middleware/context.go: add HandleAPI method

- routers/user: little code format
- conf/locale: update French locale

The normal go get protocol is to show the go-import meta tag when ?go-get=1 is appended to the url. This commit implements that behaviour and cleans the go-get option from the repository settings page.

- conf/locale: update Japanese locale