Fixed message definitions; added a compile-time check for maximum serialized message length

dsdl/uavcan/mavlink/1780.Message.uavcan

@@ -7,4 +7,4 @@ uint8 sysid
 uint8 compid
 uint8 msgid
 
-uint8[<256] payload
+uint8[<=105] payload

dsdl/uavcan/protocol/debug/1789.KeyValue.uavcan

@@ -2,6 +2,7 @@
 # Generic named parameter (key/value pair).
 #
 
-uint8[<=92] key
+bool alignment
+uint8[<=100] key
 
-uavcan.protocol.param.Value value
+float64[<=1] value

dsdl/uavcan/protocol/debug/1790.LogMessage.uavcan

@@ -4,4 +4,4 @@
 
 LogLevel level
 uint8[<32] source
-uint8[<128] text
+uint8[<94] text

libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/data_type_template.tmpl

@@ -94,7 +94,11 @@ struct UAVCAN_EXPORT ${t.cpp_type_name}
     % endfor
     {
         enum { MaxByteLen = ::uavcan::BitLenToByteLen<MaxBitLen>::Result };
-        ::uavcan::StaticAssert<int(MaxByteLen) <= int(::uavcan::MaxPossibleTransferPayloadLen)>::check();
+    % if (t.kind == t.KIND_MESSAGE) and (t.has_default_dtid):
+        ::uavcan::StaticAssert<int(MaxByteLen) <= int(::uavcan::MaxMessageBroadcastTransferPayloadLen)>::check();
+    % else:
+        ::uavcan::StaticAssert<int(MaxByteLen) <= int(::uavcan::MaxServiceTransferPayloadLen)>::check();
+    % endif
 
         ::uavcan::StaticAssert<_tmpl == 0>::check();  // Usage check