There’s not much to making the toolbar button styles switchable: the
change to the PageTemplate introduces a new configuration tiddler that
controls the button styling. Most of this commit is the user interface
for changing that setting, including the translatable text. I think
this again demonstrates that we need to be very selective about which
configuration options have a UI included in the core. Otherwise, a few
dozen more of these settings will start to become a significant
fraction of the core.
