[#] Fix spinner not appearing while installing language

This old change make it to stop working: https://github.com/joomla/joomla-cms/commit/08658c34cbc45db8e578277a468517a756e2846d
Fix code style: move spaces to tabs in all JS function
Merge pull request #2774 from javigomez/fix_spinner_in_language

[#] Fix spinner not appearing while installing language
For Info: the issue could be reproduced in Firefox on Windows XP. Merging.