fix(gulp): make gulp a dep if app is using gulp

gulpfile.coffee

@@ -1,14 +1,11 @@
 # rapid sequence
 # ==============
-module.exports = (options={}) ->
+module.exports = (gulp, options={}) ->
 	# try to load gulp from app's node_modules directory
-	# if it isn't there, load it from rapid-build's node_modules
-	# ==========================================================
-	try
-		gulp = require '../gulp'
-	catch e
-		gulp = require 'gulp'
+	# if gulp isn't supplied, load it from rapid-build's node_modules
+	# ===============================================================
 	rbDir     = __dirname
+	gulp      = require 'gulp' if not gulp
 	bootstrap = require("#{rbDir}/bootstrap")()
 	config    = require("#{rbDir}/config") rbDir, options
 	tasks     = require("#{config.req.init}/tasks") gulp, config

gulpfile.js

@@ -1,5 +1,26 @@
-// init rapid-build
-module.exports = function(options) {
+/**
+ * init rapid-build
+ * arguments are: gulp and options
+ * argument order does not matter
+ * pass in gulp if your app is using gulp
+ * options are optional
+ */
+module.exports = function() {
+	var gulp, options;
+
+	if (arguments.length) {
+		var getGulp = function(args) {
+			if (!!args[0].seq) return args[0]
+			else if (!!args[1] && !!args[1].seq) return args[1]
+		}
+		var getOptions = function(args) {
+			if (!args[0].seq) return args[0]
+			else if (!!args[1] && !args[1].seq) return args[1]
+		}
+		gulp    = getGulp(arguments)
+		options = getOptions(arguments)
+	}
+
 	require('coffee-script/register')
-	return require('./gulpfile.coffee')(options)
+	return require('./gulpfile.coffee')(gulp, options)
 }