Small improvements to Available Languages option screen

Apologies - not trying to hijack your issue - just scratching an itch! Fixes #124

Removed the 'select all' checkbox in favour of a title in the available languages column. Since there aren't any bulk actions to perform for languages, I don't see much need for a 'select all' checkbox here in the first place.

Also moved the 'language name' column to the left-most position. I feel it makes sense for this column to come first - what do you think?