Fix missing semicolon in dim level setting
Initial options page work

Show the user their current site customizations and offer a chance to
reset them all. Remove the dangerous button to reset all customizations
out of the popup.
Add option to disable high DPI workaround
Enable forcing hardware acceleration in options

Forcing the hardware accelerated rendering path with the backface
visibility style was formerly only used as the high DPI workaround. It
may have performance benefits as well, so it's helpful to be able to
force hardware acceleration.
Workaround for html background ending