C++: bumped nominal protocol version to 3.0, release number 15

(due to the changed remote method signatures)

Note: the Protobuf protocol has in fact not changed, so old
programs that strictly send and receive IUs and don't do any
RPC pertaining to remote IUs, ever, might run just fine in
the mean time :)  Still ... better rebuild them soon anyway.

ipaacalib/cpp/include/ipaaca/ipaaca.h

@@ -62,14 +62,14 @@ IU payload contents: Payload, PayloadEntryProxy
 #define __ipaaca_h_INCLUDED__
 
 /// ipaaca/IU/RSB protocol major version number
-#define IPAACA_PROTOCOL_VERSION_MAJOR         2
+#define IPAACA_PROTOCOL_VERSION_MAJOR         3
 /// ipaaca/IU/RSB protocol minor version number
 #define IPAACA_PROTOCOL_VERSION_MINOR         0
 
 /// running release number of ipaaca-c++
-#define IPAACA_CPP_RELEASE_NUMBER             13
+#define IPAACA_CPP_RELEASE_NUMBER             15
 /// date of last release number increment
-#define IPAACA_CPP_RELEASE_DATE     "2015-12-04"
+#define IPAACA_CPP_RELEASE_DATE     "2017-01-26"
 
 #ifndef __FUNCTION_NAME__
 	#ifdef WIN32   // Windows