python, pip and pyserial dependency

[alnjxn]

README should add dependencies for python and pyserial

[goliatone]

Yes, python and PySerial are indirect dependencies, from node-esp.
One reason we say this is, for now, a Mac OS only workshop is that it has Python installed already.

node-esp has a post install script that checks for PySerial and if it's not present it should install it. Now that I think about it, it uses pip which is not the default installer, it should use easy_install instead. I will open an issue against node-esp