MATLAB like imresize

implementation in codes/dataops/common

Comparison with matlab imresize (better use im2double first) for bicubic downsampling.

test on a 1404*2040 (DIV2K, 0001.png) image.

scale	error (# of pixels)	time	matlab time
x1/2	11	0.109s	0.028s
x1/3	0	0.0800s	0.0204s
x1/3.2	68	0.0792s	0.0202s
x1/4	6	0.0630s	0.0194s
x1/8	0	0.0438s	0.0152s

test on a 256*256, butterfly (Set5) image.

scale	error (# of pixels)	time	matlab time
x2	3	0.0267s	0.0094s
x3	3	0.0497s	0.0112s
x3.2	9	0.0544s	0.0109s
x4	31	0.0777s	0.0137s
x8	101	0.287s	0.0372s