0.3.0: BREAKS PROTOCOL BACKWARD COMPATIBILITY

This version is not compatible with versions prior to 0.3.0, so
'git pull' and restart if you are following the alpha.

Changes from 0.2.5:

 - All multicast frames are now signed by the original sender. This
   will permit very efficient and fault tolerant rate limitation
   across networks, and imposes a kind of "hash cash" cost on those
   who wish to flood the network by forcing them to keep regenerating
   new identities.

 - Simplified peer last unicast / last multicast accounting.

 - Improvements to multicast propagation algorithm to achieve better
   coverage with less redundant messages.

 - The bloated Switch class went on a diet, having packet decoding
   broken out into PacketDecoder and multicast propagation algorithm
   broken out into Multicaster.

 - Multicaster is implemented as a template mockable class to permit
   future simulations of huge scale multicast using the actual code
   instead of mockups in another language.

 - Introduced a faster non-cryptographic random source for things
   like multicast propagation and address choosing.

 - Some code cleanup, removal of outdated comments, etc.

version.h

@@ -36,11 +36,11 @@
 /**
  * Minor version: 8-bit (0-255)
  */
-#define ZEROTIER_ONE_VERSION_MINOR 2
+#define ZEROTIER_ONE_VERSION_MINOR 3
 
 /**
  * Revision: 16-bit (0-65535)
  */
-#define ZEROTIER_ONE_VERSION_REVISION 5
+#define ZEROTIER_ONE_VERSION_REVISION 0
 
 #endif