Transceiver52M: Set const qualifier on appropriate radio vector methods

Pointer accessor and noise average methods for radio and noise vectors
respectively.

Signed-off-by: Thomas Tsou <tom@tsou.cc>
diff --git a/Transceiver52M/radioVector.cpp b/Transceiver52M/radioVector.cpp
index d6fb742..ee78407 100644
--- a/Transceiver52M/radioVector.cpp
+++ b/Transceiver52M/radioVector.cpp
@@ -56,7 +56,7 @@
 	return mTime > other.mTime;
 }
 
-signalVector *radioVector::getVector(size_t chan)
+signalVector *radioVector::getVector(size_t chan) const
 {
 	if (chan >= vectors.size())
 		return NULL;
@@ -79,7 +79,7 @@
 {
 }
 
-float noiseVector::avg()
+float noiseVector::avg() const
 {
 	float val = 0.0;