bio-0.5: A bioinformatics library     This implements a number
of filters used in the Titanium pipeline, based on published
documentation.   Discarding filters  type DiscardFilter =
ReadBlock -> BoolSource  DiscardFilters determine whether a read
is to be retained or discarded  discard_empty ::
DiscardFilterSource  This filter discards empty sequences.
discard_key :: String -> DiscardFilterSource  Discard sequences
that don't have the given key tag (typically TCAG) at the start
of the read.  discard_dots :: Double -> DiscardFilterSource
1. The dots filter discards sequences where the last positive
flow is before flow 84, and flows with >5% dots (i.e. three
successive noise values) before the last postitive flow. The
percentage can be given as a parameter.  discard_mixed ::
DiscardFilterSource    1. The mixed filter discards sequences
with more than 70% positive flows. Also, discard with 30% noise,
20% middle (0.45..0.75) or <30% positive.  discard_length :: Int
-> DiscardFilterSource  Discard a read if th