hopefully doesn't break in the other browsers

Please someone who know the code, double check this one.
It does look that translation for 2 options were missing.

This reverts commit de4634ec.

IE doesn't like it when you create a DOM element in one window and
try to insert it in another window.

The icon does not match the others because the NuvolaX icon theme seems
to have vanished from the Internet. Ideally all those admin icons could
use a replacement. But that should be a different PR I guess.

Resolves #1192

`/lib/plugins/<plugin>/deleted.files`
which list files that can be removed e.g.
```
# This is a list of files that were present in previous plugin releases
# but were removed later. An up to date plugin should not have any of
# the files installed
action.php
folder/file.txt
```

adds aria handling to makeToggle and allows to supress it in dw_toggle

* improved spacing of popup
* made primary buttons clearer
* xhtml and validity fixes
* improved some lang strings
* moved 'open as popup' after intro
* fixed page reload after clicking 'open as popup' button

Выравнивание и разбиение по образцу en/lang.php, унификация "директорий" и "папок", "расширений" и "дополнений"