Ethernet library refactoring

- removed arch folder
- merged socket.c and w5100.c for SAM and AVR, this is preparatory
  to make library vanilla

libraries/Ethernet/src/utility/util.h

@@ -0,0 +1,14 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+#define htons(x) ( ((x)<< 8 & 0xFF00) | \
+                   ((x)>> 8 & 0x00FF) )
+#define ntohs(x) htons(x)
+
+#define htonl(x) ( ((x)<<24 & 0xFF000000UL) | \
+                   ((x)<< 8 & 0x00FF0000UL) | \
+                   ((x)>> 8 & 0x0000FF00UL) | \
+                   ((x)>>24 & 0x000000FFUL) )
+#define ntohl(x) htonl(x)
+
+#endif