Solved Fron-End Test

Removed background-attachment:scroll' property in order to fix Firefox banner problem. Is pending to check whether or not this dynamic background works in Internet Explorer at all.
Checkout button created using only CSS properties.
Added jQuery.validate library for login page validation (including the password field as it was requested).
Added configuration for jQuery.validate localization.
Visual improvements over the login page by means of some Bootstrap framework classes and icons.