Feature Request: Decorator for adding Trace names

[flyinbutrs]

As I'm marking up my functions for tracing, I find my self often doing this:

def function_of_app():
  with context.iopipe.mark('function_name'):
     # function code

It would be very nice to be able to do something like this:

@iopipe.mark('function_name')
def function_of_app():
   # function code