Remove the "shrinking window" from the concatenator

[robsheldon]

Related to issue #2 -- the concatenator currently uses a "shrinking window" when gluing passwords together, and for no good reason. Just have it always look at $lookahead_chars characters, preferentially check the most common passwords list, and after some number of passwords have been spit out make sure that one of the common ones are too.

This should help squeeze some more passwords out during concatenation.