Forgot to set tvar for endpoint types.
Added missing emitting code to handle endpoint types.  Importantly,
disallowing passing endpoint references through network: when receive
a dispatch command for a method that takes an endpoint argument, will
populate that argument with null.
StructType and EndpointType should subclass from generic Type.
Created a wildcard type, which is returned from any method call on an
endpoint object.  The reason why these calls are necessary is that
without proper library mechanisms, cannot deduce return type from
method call.  Wildcard types match any and are used in assignment
statements.
Special-cased method calls on endpoint objects.  To perform method
call correctly, must:
   1) cast internal endpoint object from endpoint to specific endpoint
      that supports that method
   2) actually make call to internal methods in other endpoint.
Added test code to ensure that endpoint calls worked.
Lexing and parsing for verbatim built-in, which just takes its
argument and literally puts it into the program text.
Added a test to ensure that atomically is respected between endpoint call boundaries.