Added NE2000 network support.

NE2000 emulation originally from Bochs, ported by SA1988.
SLiRP originally from QEMU, ported by neozeed.

src/nethandler.h

@@ -0,0 +1,20 @@
+#include <stdint.h>
+
+//void vlan_handler(int (*can_receive)(void *p), void (*receive)(void *p, const uint8_t *buf, int size), void *p);
+void vlan_handler(void (*poller)(void *p), void *p);
+
+extern int network_card_current;
+
+int network_card_available(int card);
+char *network_card_getname(int card);
+struct device_t *network_card_getdevice(int card);
+int network_card_has_config(int card);
+void network_card_init();
+
+char *network_card_get_internal_name(int card);
+int network_card_get_from_internal_name(char *s);
+
+void initpcap();
+void closepcap();
+
+void vlan_reset();