Rename C++ fields and internal methods

Summary: From sonar* to flipper*.

Reviewed By: priteshrnandgaonkar

Differential Revision: D9944461

fbshipit-source-id: 870997e3d1d5aaef73dd445e6d94615f93fe6abc

xplat/Flipper/Log.cpp

@@ -9,9 +9,9 @@ namespace flipper {
 
   void log(const std::string& message) {
   #ifdef __ANDROID__
-    __android_log_print(ANDROID_LOG_INFO, "sonar", "sonar: %s", message.c_str());
+    __android_log_print(ANDROID_LOG_INFO, "flipper", "flipper: %s", message.c_str());
   #else
-    printf("sonar: %s\n", message.c_str());
+    printf("flipper: %s\n", message.c_str());
   #endif
   }