Issue 1476 of learningequality/ka-lite - Don't show dropdown if English is the only language

Attaching base.html and the git difference file.
The code is working , its a bit different .

Like if there is only one language ( any one : could be English , could be German ) then the drop down menu won't be displayed. Because if you don't have option to change the language then whats the purpose of drop down box.

If there is more than one language drop down will work as usual.