Truncate an array along the dimensions specified

A handy function works as the "inverse" of `padarray`. Truncate the ND array in a concise and intuitive fasion.

I used `padarray`, a built-in function in Image Processing Toolbox, very often.

It was a bit tedious and annoying to turn the padded array into its original size, particularly for ND array.

For example, you might write as follow:

`A = B(1+padsize(1):end-padsize(1), 1+padsize(2):end-padsize(2), 1+padsize(3):end-padsize(3), ......, 1+padsize(k):end-padsize(k));`, which looks messy.

Therefore, I created this handy function as the "inverse" of `padarray` to truncate an array in a concise and intuitive fasion.

The usage mimics `padarray`'s:

`B = truncatearray(A, truncatesize)`

`B = truncatearray(A, truncatesize, direction)`

Examples:

A = rand(randperm(randi([4, 10], 1)));
padsize = randperm(randi([0, ndims(A)], 1));
paddirection= 'pre';
B = padarray(A, padsize, paddirection);
C = truncatearray(B, padsize, paddirection);
if isequal(C, A), disp('Pass'), else, disp('Error');end