Improve handling of vectors in streaming handlers

[tmadlener]

In some places vector elements are copied element by element into the sio stream, e.g.

LCIO/src/cpp/src/SIO/SIOLCParameters.cc

Lines 62 to 65 in 1287e94

	SIO_DATA( device , &nInt , 1 ) ;
	for(int j=0; j< nInt ; j++ ) {
	SIO_SDATA( device, intVec[j] ) ;
	}

sio should be able to handle vectors as a whole, without having to read each element separately. We do this in podio: https://github.com/AIDASoft/podio/blob/master/src/SIOBlock.cc#L47-L67

	SIO_SDATA(device, intVec);

Originally posted by @tmadlener in #143 (comment)