E131 Sender

[ThomasH-W]

In order to use the esp8266 as a sender, I have extended this libary.
As I am not used to program in cpp, the code might look strange - but it works.
Basically I have added buffers for transmittion (TX) based on a slightly different package structure.
This is easier when preparing root, frame and dmp for the submission.

You can find the updated files here:
http://www.hoeser-medien.de/2017/03/e131-sender-based-on-library-created-by-forkineye/

This might be usefull for others but probably not coded well enough to inject this into the official library.