Change sampleCount arguments, variables, return values to size_t...

... whenever they really describe the size of a buffer that fits in memory, or
of a block file (which is never now more than a megabyte and so could be fit in
memory all at once), or a part thereof.

src/effects/ClickRemoval.cpp

@@ -255,7 +255,7 @@ bool EffectClickRemoval::ProcessOne(int count, WaveTrack * track, sampleCount st
    return bResult;
 }
 
-bool EffectClickRemoval::RemoveClicks(sampleCount len, float *buffer)
+bool EffectClickRemoval::RemoveClicks(int len, float *buffer)
 {
    bool bResult = false; // This effect usually does nothing.
    int i;