Removed C-style casts

In c++ code would be cleaner to use
c++ retinterpret cast instead of old
c-style notation

Change-Id: Ibeef5e0c374addf108c0a8876a6be45063d8e396
diff --git a/wear_touch.cpp b/wear_touch.cpp
index cf33daa..e2ab44d 100644
--- a/wear_touch.cpp
+++ b/wear_touch.cpp
@@ -118,7 +118,7 @@
 }
 
 void* WearSwipeDetector::touch_thread(void* cookie) {
-    ((WearSwipeDetector*)cookie)->run();
+    (static_cast<WearSwipeDetector*>(cookie))->run();
     return NULL;
 }