Fix warnings, reduce header file dependencies

src/Snap.cpp

@@ -8,14 +8,14 @@
 
 **********************************************************************/
 
+#include "Snap.h"
+
 #include <cstdlib>
 
+#include "Project.h"
 #include "LabelTrack.h"
 #include "TrackPanel.h"
 #include "WaveTrack.h"
-#include "widgets/NumericTextCtrl.h"
-
-#include "Snap.h"
 
 #include <wx/arrimpl.cpp>
 
@@ -214,12 +214,12 @@ size_t SnapManager::Find(double t, size_t i0, size_t i1)
 size_t SnapManager::Find(double t)
 {
    size_t cnt = mSnapPoints.GetCount();
-   int index = Find(t, 0, cnt);
+   size_t index = Find(t, 0, cnt);
 
    // At this point, either index is the closest, or the next one
    // to the right is.  Keep moving to the right until we get a
    // different value
-   int next = index + 1;
+   size_t next = index + 1;
    while (next + 1 < cnt && Get(next) == Get(index))
    {
       next++;

src/Snap.h

@@ -18,13 +18,16 @@
 #include <wx/defs.h>
 #include <wx/dynarray.h>
 #include <wx/string.h>
-
-#include "Project.h"
-#include "Track.h"
-#include "ViewInfo.h"
-#include "WaveClip.h"
 #include "widgets/NumericTextCtrl.h"
 
+class AudacityProject;
+class Track;
+class TrackArray;
+class TrackClipArray;
+class WaveClip;
+class TrackList;
+class ZoomInfo;
+
 class TrackClip
 {
 public: