block diagonal representation

Converts a matrix into a cell array of different sized matrices that make up the blocks.

Essentially if one has a matrix M that they wish to store more efficiently in memory/use for function bldiagmult.m (same author), then use
cellform = blkdiagconv( M );
this is such that using the inbuilt Matlab function one has
M == blkdiag(cellform{:})
it is essentially the inverse function to blkdiag.