[Haskell] Add explicit Show Dimension definition.
[Haskell] Add ToJSON declarations for Options, Dimension, FractalType,
ColorMap, and Complex.
[Haskell] Use defaultMain for the test runner.
[Haskell] Improve HUnit tests; add QuickCheck properties.
[Haskell] Remove "a.out" from clobber list in Rakefile.

It's not normally generated.