add javascript examples - use with node.js

you will note that a couple of node modules are required to run these examples
the examples are complicated by the fact that we are dealing wit subdevices
hopefully libraries will exist in the future to make this much simpler

you can run these two examples as follows:

node test_data <rate> | node test_post # will keep posting at every <rate> ms until you ^C
node test_data | node test_get will get everything that's been posted

(test_data.js needs a password)