Remove unnecessary imports

app/__init__.py

 # app/__init__.py
 
-# third-party imports
-from flask import Flask, redirect, url_for, request
-from flask import render_template
-
 # local imports
+from __future__ import print_function
+
+# third-party imports
+from flask import Flask, redirect, url_for, request, render_template, flash, session
+from flask_bootstrap import Bootstrap
 
 
 def create_app(config_name):