Several fixes to flaskr

got rid of catchall in connect_db
moved from requst.form to json.loads( request.data ) (issue with Angular)
Switch to angular style post in user_create
Implementation of UsersCntl

Add doLogin in UsersCntl
Add doSignUp in UserCntl
Error fields in users.html

Add error field for login in users.html

Add sign_up_error in users.html