improve layout of the sign up form so that the wrapped part of it keeps space between the part above.
adopting collapse feature on the sign up form.
replace tag a with tag button.
remove href attriute from button tag.
improve style of button so that it looks like a link and centers vertically.
initial commit for wiring AngularJS+Firebase libraries up.
add missed ng-controller attribute.
resolve a conflict of naming between password model and input control which resulted in an weird way that what's saved in the current clipboard will automatically fills in the password field.
bugfix: createUser() was not defined.
refactor function parameters so that function accepts username/password as arguments.
bugfix: createUser() was not defined. The reason is the required js library was missed. Also improve initialization so it could be notified if any error occurs in initialization phase.
relocate the login promotion part so it can share the same  $scope with login form part in AngularJS, so that greeting message can constructed with authentiatio info which is saved in the $scope that is bound to the Logincontroller controller.
change the layout of both parts of login promotion and sign up form entirely.
bugfix.
improve layout.
improve layout.
relace email address with username when showing greeting after user has signed up.