Version 0.4.1 - RateLimiter for multicast, bug fixes.

This version adds a draft of the multicast rate limiting architecture. A
few minor bugs are also fixed. The Linux version builds in debug mode for
now.

version.h

@@ -41,6 +41,6 @@
 /**
  * Revision: 16-bit (0-65535)
  */
-#define ZEROTIER_ONE_VERSION_REVISION 0
+#define ZEROTIER_ONE_VERSION_REVISION 1
 
 #endif