event; definition and custom

[vprimachenko]

I propose (in association with #107 ) for events to be bound via

button {
    on[click] : ${alert("hi!");};
}

(implimentation detail) where click as keyword resolve to the string "click"

custom events would require quotation marks:

app {
   on["userLogout"]:${ cleanWorkspace(); }
}

which would allow namespaces events (for which i vote with all my limbs) to be implemented with ease

app {
   on["mouseup.drag"]:${ handleDrop(); }
}