Split delimiter separated strings into a matrix

Function to split a delimiter separated string into a matrix of doubles.

Function: outmatrix = strsplit(inpstr[,delimiter])

Input:
inpstring, this is the input string which is a delimiter separated string: 345.56,376.5,4334.34 .
delimiter, optional if not given, ',' is taken.
outmatrix: if all values in inputstring are numerical a double array is given otherwise a cell array.