a = enumBase2(n) constructs a cell array that enumerates from 0 to (2^n - 1) in binary.

a = enumBase2(n,outputformat) constructs an array that enumerates from 0
to (2^n - 1) in binary. The type of array output is given by
outputformat. By default, outputformat=1, which outputs a cell array.
If outputformat=2, then the output is a numeric array.

Examples
-------
numBase2(4) returns the following cell array:
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

numBase2(4,2) output the same as above, except as a numeric array.

Useful for combinatorics.