Fix sliding window indices

Previously, sliding window indices excluded some final indices. New approach ensures all indices are returned, but an extra clipping step is necessary to prevent reading beyond the end of the feature matrix.

Closes #1.

find_audio.m

@@ -224,7 +224,18 @@
 
     function idx = sliding_window_indices(length, win_length, win_step)
         win = 0:(win_length - 1);
-        idx = bsxfun(@plus, 1:win_step:(length - win_length + 1), win');
+
+        % length - win_length + 1 provides all valid indices (but misses
+        % some at the end of the length)
+
+        % length - win_step + 1 provides all indices (as well as a few past
+        % the end of length; as result, clip indices past length)
+
+        idx = bsxfun(@plus, 1:win_step:(length - win_step + 1), win');
+
+        if idx(end) > length
+            idx(idx > length) = length;
+        end
     end
 
     function [match_starts, match_ends, match_scores] = match_via_dtw(feat_template, feat_audio, thresh_score)