#2011 - Add IE version check to new js, re-introduce old-IE shim previously removed.

- added $.gallery_ie_version() to gallery.common.js, which detects IE versions 5 and up.
- used new function to re-introduce the old-IE shim in ui.init.js (previously removed since $.browser is gone).
- reformatted ui.init.js a bit (replaced tabs with spaces).