Replace underscore with lodash

Replace 2 uses of underscore and 1 use of a lodash submodule with full
lodash module.

lib/bundler.js

@@ -1,7 +1,7 @@
 var fs = require('fs');
 var path = require('path');
 var commondir = require('commondir');
-var cloneDeep = require('lodash.clonedeep');
+var cloneDeep = require('lodash').cloneDeep;
 
 /**
  * Add boot instructions to a browserify bundler.

lib/compiler.js

@@ -1,5 +1,5 @@
 var assert = require('assert');
-var cloneDeep = require('lodash.clonedeep');
+var cloneDeep = require('lodash').cloneDeep;
 var fs = require('fs');
 var path = require('path');
 var toposort = require('toposort');

lib/executor.js

@@ -1,5 +1,5 @@
 var assert = require('assert');
-var _ = require('underscore');
+var _ = require('lodash');
 var semver = require('semver');
 var debug = require('debug')('loopback:boot:executor');
 var async = require('async');

package.json

@@ -26,10 +26,9 @@
     "async": "~0.9.0",
     "commondir": "0.0.1",
     "debug": "^2.0.0",
-    "lodash.clonedeep": "^2.4.1",
+    "lodash": "^2.4.1",
     "semver": "^4.1.0",
-    "toposort": "^0.2.10",
-    "underscore": "^1.6.0"
+    "toposort": "^0.2.10"
   },
   "devDependencies": {
     "browserify": "^4.1.8",