GH-258 Navbar link cursor

Fix for issue 258.

Sorry, I forgot that Github only allows one PR per branch to be open. The second commit is just a less intense version of the noisy_grid background image. I like the new design, glad you got someone better than me to put a coat of paint on SV, but the image for my two cents is too intrusive on the actual content so I made a version that has opacity turned down to 40%. No problem if you prefer not to use it.