As of Arduino 1.0 the file extension has changed from
.ino so this line:
autocmd! BufNewFile,BufRead *.pde setlocal ft=arduino
autocmd! BufNewFile,BufRead *.ino setlocal ft=arduino
Would be nice to see an update to this to address any changes to the Arduino API (if any) as Arduino is now version 1.6.1 as of writing.