Attack speed?

I was reading in the Dagger attack speed thread, and someone mentioned that when you're at 16 Dagger Mastery, the attack speed goes from 1.33 seconds to 1 second. Is the speed increase true for bows, or any other weapon for that matter?

No, and its not directly true for daggers either.
What happens is that increasing your rank in Dagger Mastery increase the probability of performing a double strike (hitting twice in one attack). At 16 dagger mastery, the chance is about 1 in 3, thus in 4 seconds you attack 3 times (1.33 s / attack), one of those attacks double strikes to give and effective 4 attacks in those 4 seconds => attack rate ~ 1s / attack.

Is there any chance of a double attack occurring while using a skill for a Lead Attack or an Off Hand Attack?