Enable C++14

Node 16.x/Electron 11.x updates V8 to v8.7, enforcing usage of C++14 in addons.

Author: EmingK

binding.gyp

@@ -6,12 +6,12 @@
             "<!(node -e \"require('nan')\")"
         ],
         "cflags_cc": [
-            "-std=c++11"
+            "-std=c++14"
         ],
         "conditions": [
             [ 'OS=="mac"',
                 { "xcode_settings": {
-                    'OTHER_CPLUSPLUSFLAGS' : ['-std=c++11','-stdlib=libc++'],
+                    'OTHER_CPLUSPLUSFLAGS' : ['-std=c++14','-stdlib=libc++'],
                     'OTHER_LDFLAGS': ['-stdlib=libc++'],
                     'MACOSX_DEPLOYMENT_TARGET': '10.8'
                 }}