Remove duplicate npm dependencies: d3 and he

These are already defined as dependencies (same versions), so there's
no point keeping them as devDependencies. npm complains about that.

package.json

@@ -41,7 +41,6 @@
     "clone": "^0.2.0",
     "codeclimate-test-reporter": "0.0.4",
     "connect-livereload": "^0.5.3",
-    "d3": "~3.4.13",
     "dateformat": "^1.0.11",
     "dox": "^0.8.0",
     "event-stream": "^3.2.0",
@@ -75,7 +74,6 @@
     "gulp-tag-version": "^1.2.1",
     "gulp-uglify": "~1.0.1",
     "gulp-vartree": "^2.0.1",
-    "he": "^0.5.0",
     "hogan.js": "^3.0.2",
     "jasmine": "~2.0.1",
     "jison": "~0.4.15",