Fixes GCC 8.X compiler warnings.

Changes:
executor.cpp - reorder member initialization in constructor
binding.gyp - add  compiler flags -Wextra -Wno-cast-function-type
package.json - upgraded nan to 2.14.2

Author: wayneparrott

binding.gyp

@@ -35,7 +35,7 @@
         '-fstack-protector-strong',
         '-fPIE -fPIC',
         '-O2 -D_FORTIFY_SOURCE=2',
-        '-Wformat -Wformat-security'
+        '-Wformat -Wformat-security -Wextra -Wno-cast-function-type'
       ],
       'cflags_cc!': [
         '-fno-exceptions'

package.json

@@ -64,7 +64,7 @@
     "is-close": "^1.3.3",
     "mkdirp": "^1.0.4",
     "mz": "^2.7.0",
-    "nan": "^2.14.1",
+    "nan": "^2.14.2",
     "ref-napi": "^3.0.0",
     "ref-array-di": "^1.2.2",
     "ref-struct-di": "^1.1.1",

src/executor.cpp

@@ -43,10 +43,10 @@ struct RclResult {
 
 Executor::Executor(HandleManager* handle_manager, Delegate* delegate)
     : async_(nullptr),
+      main_thread_(uv_thread_self()),
       handle_manager_(handle_manager),
       delegate_(delegate),
-      context_(nullptr),
-      main_thread_(uv_thread_self()) {
+      context_(nullptr) {
   running_.store(false);
 }