(1) now builds and works on Linux, (2) fix a threading problem causing carsh on shutdown, (3) cleanup in selftest, re-enable Phy and Http tests.

service/OneService.cpp

@@ -53,10 +53,15 @@
 #include "OneService.hpp"
 #include "ControlPlane.hpp"
 
+// Include the right tap device driver for this platform -- add new platforms here
 #ifdef __APPLE__
 #include "../osdep/OSXEthernetTap.hpp"
 namespace ZeroTier { typedef OSXEthernetTap EthernetTap; }
 #endif
+#ifdef __LINUX__
+#include "../osdep/LinuxEthernetTap.hpp"
+namespace ZeroTier { typedef LinuxEthernetTap EthernetTap; }
+#endif
 
 // Sanity limits for HTTP
 #define ZT_MAX_HTTP_MESSAGE_SIZE (1024 * 1024 * 8)