Allow to install the template in the user directory

Signed-off-by: Luca Niccoli <lultimouomo@gmail.com>
Add arduino version to predefined macros

QtCreator cannot figure it on its own, because it's defined dinamically
by Arduino.mk, so it cannot expand headers correctly.

Signed-off-by: Luca Niccoli <lultimouomo@gmail.com>