Removed demo system.
Added #sin, #cos, and #abs to float.
Change expressions handling to evaluate.
Removed rule-io.rb because rule input/output data changed to be based on sequence.
Removed unneeded methods.
Removed unneeded method from TicketExpr.
Refactored ticket expression.
More friendly message for MethodNotFound.
Removed unneeded methods from PioneString and fixed some tests.