Don't use latest NaN version. Use old version of node for tests.

package.json

@@ -82,7 +82,7 @@
     "decompress": "^4.2.0",
     "fs-extra": "^4.0.2",
     "ini": "^1.3.4",
-    "nan": "^2.3.3",
+    "nan": "2.8.0",
     "node-fetch": "^1.6.3",
     "node-pre-gyp": "^0.6.36",
     "progress": "^2.0.0",

scripts/test.sh

@@ -211,7 +211,7 @@ if [[ -z "$(command -v nvm)" ]]; then
   set -e
 fi
 if [[ "$(command -v nvm)" ]]; then
-  nvm install 7.10.0
+  nvm install 6.11.3
 fi
 
 # Remove cached packages