Pristine copy of Fractal from Bamboo

According to the paper, this is a port from the StreamIt benchmark
suite.

See #4.
Complete port of FilterBank

It's mostly embarrassingly parallel except for the output portion. There
is a "merge" operation but it is mostly order independent.

Include the original Bamboo task specification for comparison. There is a
lot of freedom to specify the sequential version so I did one that seems
the simplest.

See #4.