IE8 Fixes

Adding ms-filter to make background pgzoomview work better -- seems to
been added since my last fork.

changed .pgzoomspacer to display: inline-block

using .pgzoomspacer as a div instead of image now, cleaner method and
was getting white line intermittently
Merge pull request #12 from bobsawey/master

Made some changes for IE8, what do you think?