Modified alpha trimmed mean filter to memoize the line it is currently on
Optimized ArithmeticMeanFilter.cs
Optimized BasicSpatialSubFilter.cs
Optimized BitplaneManipulatino.cs by memoizing results
Modified BitplaneManipulator to statically precompute all bitplane combos

I realized that since there are only 256 values for the bitplane values and 256
entries for each bitplane combination then it is possible to precompute the
entire table and only pull out the table tied to the desired intensity.
Modified the static TranslationMatrix to be private and correctly initialized

I set it up so that each BitplaneManipulator object created attempts to create
the TranslationMatrix. If it has already been created then nothing happens,
otherwise the table is created as part of the first object creation.
Changed the TranslationMatrix construction to use a static ctor

The reason for this is to make the class cleaner and it's the correct way to do
things.