bump to v3.1.7, upgrade nan/node-pre-gyp/mocha [publish binary]

CHANGELOG.md

 # Changelog
 
+## 3.1.7
+
+- Upgrade sqlite to 3.15, enable FTS4, FTS5 (@wmertens)
+- Upgrade to node-pre-gyp@0.6.31 and nan@2.4.0
+
 ## 3.1.6
 
 - Starts bundling node-pre-gyp again to avoid #720

package.json

 {
     "name": "sqlite3",
     "description": "Asynchronous, non-blocking SQLite3 bindings",
-    "version": "3.1.6",
+    "version": "3.1.7",
     "homepage": "http://github.com/mapbox/node-sqlite3",
     "author": {
         "name": "MapBox",
@@ -37,14 +37,14 @@
         "url": "git://github.com/mapbox/node-sqlite3.git"
     },
     "dependencies": {
-        "nan": "~2.3.3",
-        "node-pre-gyp": "~0.6.28"
+        "nan": "~2.4.0",
+        "node-pre-gyp": "~0.6.31"
     },
     "bundledDependencies": [
         "node-pre-gyp"
     ],
     "devDependencies": {
-        "mocha": "2.x",
+        "mocha": "3.x",
         "aws-sdk": "2.x"
     },
     "scripts": {