usb-creator creates a FAT filesystem for persistence but should be ext2 or ext4

[Jan Schürmann]

Binary package hint: usb-creator

the usb-creator formats the persistent partition with FAT-32 so i could only use 4GB persistent partition on my 8GB stick.

ubuntu itself only needs a FAT-16 partition with max. 800MB and the rest could be formatted as ext2 or ext4 for persistence.

that was the thing the live_usb script does if persistent disk is choosen:
making one partition with 800MB for the ro filesystem with FAT-16 for compatibility and a second partition with the rest of the sticks memory formatted as ext2.