Save MAT files more quickly

When working with large arrays, Matlab's 'save' command can be very slow, presumably because Matlab attempts to use compression. This function provides a much faster alternative, at the cost of larger files. It only improves speed for variables that are plain arrays; elements of structures or cell arrays are not altered.

Example:
% First make some data
>> ops = struct('algorithm', 'greedy');
>> A = int32(randi(20, 1000, 1200, 40));
>> B = randn(500, 1800, 60);
% Now save it
>> tic; save /tmp/test ops A B; toc
Elapsed time is 22.980294 seconds.
>> tic; savefast /tmp/test ops A B; toc
Elapsed time is 0.571098 seconds.

Happy saving!