replace CALLBACK -> epicsCallback

git grep -l -w CALLBACK -- src|xargs sed -i -e 's/\bCALLBACK\b/epicsCallback/g'

with exceptions in callback.h

src/std/dev/devBiSoftCallback.c

@@ -35,7 +35,7 @@
 
 typedef struct devPvt {
     processNotify pn;
-    CALLBACK callback;
+    epicsCallback callback;
     long options;
     int status;
     struct {