Navbar fixed switch at 330px now
New Navbar style:
 - When fixed, the opacity is set to 0.85%
 - Black border to the bottom when Navbar is fixed
Z-index fixed to the navbar
Merge branch 'develop' into feature/navbar

* develop:
  ImageGallery some code fixed
  Added the gallery viewer and some jpg for the necessary testing. Modified the original script with auto-width capatibility.