Added function NSStringFromCGPoint to  CASCCDProperties.h.
CoreAstroAlgs: renamed cas_alg_X, cas_alg_Y, and cas_alg_P to cas_alg_kx, cas_alg_ky, and cas_alg_p to conform with HFD.pdf doc. Changed return types from NSInteger to NSUInteger.
CoreAstroAlgs: fixed a comment in CASAlgorithm+Exposure.h.
CoreAstroAlgs: fleshed out CASFocusMetric a bit more, and added brightnessCentroid: (CGPoint*) brightnessCentroidPtr to the method -focusMetricForRegion: inExposureArray: ofLength: numRows: numCols:.
CoreAstroAlgs: started work on CASHalfFluxDiameter. WIP.