ExchangeRule.parseRuleString NPE

[erocs]

Minor perf bug. ExchangeRule.parseRuleString generates an NPE for any item without lore. This is a needless object creation / exception throw for something that can be prevented with a couple conditionals.

Note: The catch-all exception handler should remain.

[erocs]

#18 might be enough to not worry about this. It's still wacky though.