abstract out chain creation in dynDyanmicRelaxation
updated dynArduino to output strings instead of a parsed number

Ok, I just updated the dynArduino node to return a string and created a
sample (included) that shows how to parse into two separate numbers.

on my arduino i tested with a sketch running that outputs temp and
relative humidity, http://bildr.org/2012/11/sht15-arduino/ , it outputs
two numbers separated by a "|" like this:

17.12 | 45.37

Dynamo can parse this into diff inputs pretty easily, string to number
even handles trimming leading/trailing spaces. code added to github just
now.

-matt