Heavily commented BilinearInterpolationFilter.cs
Documented BitDepthModification.cs
Documented GlobalHistogramEqualization.cs
Modified HistogramMatchingFilter.cs

I memoized some array fields to reduce the amount of array access overhead and
wrote some documentation.
Reformatted and cleaned up HistogramMatchingFilter.cs further

I found that the ClosestValue method could have two of it's conditions merged
into a single one.
Commented and optimized LocalHistogramEqualization.cs
Optimized LogTransformation.cs

I memoized the results of the 256 values that make up a pixel for the given
image. This should make the code run significantly faster.
Modified PowerLaw to precompute the intensity results

This should greatly improve performance by reducing the number of expensive Pow
operations to 1 and the number of multiplications by that factor to 254.
Fixed two issues in LogTransformation.cs

1) The number of elements in the precomputed value table was off by one.
2) The input to ComputeValue wanted a byte when it was being provided with an
int