Insert pseudo code for objective function claculation in documentation

Include pseudo code for objective function gradient calculation.

Member ImagePyramid< VoxelType >::GenerateLevels (const nifti_image *const imageIn, unsigned int numberOfLevels, unsigned int numberOfLevelsToPerform, unsigned int minNumberOfVoxelsPerDim=1, float(*minVoxDim)[3]=nullptr)

Need to find a solution if slope is zero. If this is the case, the input data will be blacked out.

Member Optimiser::MoveCurrentPointAlongGradient (PrecisionType stepSize)

Make parallel

Member SSDImageSimilarity::GetSimilarityGradientWRTVoxels (nifti_image *referenceImg, nifti_image *sourceImg, nifti_image *similarityGradientWRTVoxelsOutputImage)

Decide how to deal with multiple time points in images

Member SSDImageSimilarity::GetSimilarityMeasureValueForImages (nifti_image *source, nifti_image *reference)

Perform checks that images are of equal size, and equal data type (equal geometry?)

Member Transformation::BilinearTransformImageAdjoint (nifti_image *sourceImage, nifti_image *sourceWeightsImage, nifti_image *warpedImage, nifti_image *warpedWeightsImage)

: Decide if original switch statement is necessary at all.

: Remove reg_round macro with inline function

Member Transformation::CubicSplineTransformImageAdjoint2D (nifti_image *sourceImage, nifti_image *sourceWeightsImage, nifti_image *warpedImage, nifti_image *warpedWeightsImage)

: Decide if original switch statement is necessary at all.

Member Transformation::CubicSplineTransformImageAdjoint3D (nifti_image *sourceImage, nifti_image *sourceWeightsImage, nifti_image *warpedImage, nifti_image *warpedWeightsImage)

: Decide if original switch statement is necessary at all.

Member Transformation::interpolation

Change into enumeration.

Member Transformation::TrilinearTransformImageAdjoint (nifti_image *sourceImage, nifti_image *sourceWeightsImage, nifti_image *warpedImage, nifti_image *warpedWeightsImage)

: Decide if original switch statement is necessary at all.