Create a directory on the SD card. This will also create any intermediate directories that don't already exists; e.g. SD.mkdir("a/b/c") will create a, b, and c.
Syntax
SD.mkdir(filename)
Parameters
filename: the name of the directory to create, with sub-directories separated by forward-slashes, /.
Returns
1 if the creating of the directory succeeded, 0 if not.