Update README.md

Author: fpistm

README.md

@@ -1,2 +1,6 @@
 # LwIP
- Lightweight TCP/IP stack (LwIP)  is a small independent implementation of the TCP/IP protocol suite.
+ Lightweight TCP/IP stack (LwIP)  is a small independent implementation of the TCP/IP protocol suite that has been initially developed by Adam Dunkels and is now continued [here](https://savannah.nongnu.org/projects/lwip/).
+ 
+ Modified to fit Arduino libraries specifications.
+ 
+ It is used by the [STM32Ethernet](https://github.com/stm32duino/STM32Ethernet) library.