Created default item for Item.java

Without a default item for Item.java, if getWeight is called after an
item is constructed without a weight or quantity, the function will
throw an exception.
Party Fix- BREAK, BobAdded, Replace, and Delete

Added a BREAK in the for loop to prevent every NULL member of the party
from becoming a Bob clone.

Added variable BobAdded to print a warning if the party is full and Bob
has not been added.

Added method Replace to replace one character with another.

Added method Delete to delete a character.