Added a new s7-light driver...

[Christofer Dutz <ch...@c-ware.de>]

Hi all,

I was helping a company sort out issues with running the S7 driver on heavy load.
Finally I gave up on tring to find the problems with the existing driver, as I was never having the same issues with any of the other drivers.

So I thought: This is the only driver with the S7Mux stuff for enabling having multiple connections and I duplicated the driver inside the s7 module.
I named the duplicate „s7-light“. It is a copy of the current driver, but removed all of the stuff that’s related to implementing the subscription support (as I have still to find a device that actually makes use of this feature).

So if you’re having problems with the current s7 driver and don’t need subsciptions, please give „s7-light“ a try and report back.

Chris