Random amount of characters when creating new pad.

[muppeth]

Currently ownpad creates pads with random characters. But it's always the same amount of characters. This makes it a bit more easy to target instances that use ownpad since you at least know the amount of chars.

First of all maybe it would be a good idea to extend the amount of characters (64, 128?) for pad names and secondly have randomizer for amount of characters used when creating the pad (say varying from 32 to 128).