new macro KEYS__ALT_GR

You can use this macro to define keys to send combinations of altGr (right alt) and the key.
E.g. in Germany to type '{' you need to press altGr + 7. If I want to define a
key to directly enter this char, I now can define it.
new macros to enter otherwise dead keys directly

On some keyboards there are dead keys, i.e. keys to enter accented keys, like è.
But to enter the accent itself, like `, you need to double tab the key. These
macros allow to define a key that does this.