Switch from browser detection using document.all to feature detection
Declare JS variables in timeline.php to avoid automatic globals
Remove ancient layer-background-color CSS property for Netscape
Merge pull request #110 from mnoorenberghe/document_all

JS cleanup (replace document.all and declare variables in timeline.php)
Merge pull request #111 from mnoorenberghe/layer_background

Remove ancient layer-background-color CSS property for Netscape