Remove the ability to switch language to the current language

The "Restart brackets" button will be disabled if you select the current
lang in the "Switch Language" dialog.

Tested on Windows 8 with Brackets 0.32 master c05cfd5
Fixed indent
Don't allow drag-and-drop of files/folders when a modal dialog is showing.
Update main.js

Thanks for the tip ;)
Merge pull request #5313 from adobe/rlim/no-drop-on-modal

Don't allow drag-and-drop of files/folders when a modal dialog is showing.
Merge pull request #5287 from SAPlayer/patch-5

Remove the ability to switch language to the current language