$THEME->standardsheets
that a theme can use to control how much of the
standard theme is included before the actual current
theme sheets.
When true, use all subsheets from "standard"
When not existent, use all subsheets from "standard" (this is to help old
themes work better out of the box)
When false, don't use standard at all
When an array of filenames, only use those (in that order).
This is the new standard theme, based on the excellent work by
Urs Hunkler (and I believe David Scotson had an influence)
who has started rationalising the old mess.
I've made this a very neutral, almost white theme.
[ Come to think of it maybe I've been looking at iPods and Mac Minis
a bit too much recently. ;-) ]
The idea is that the standard styles will be included by all
other themes (including custom themes) before local overriding
styles are applied.
This means that upgrades will cause less problems for custom themes.
It's a bit like the language packs, where "en" is always referenced
when a local language string isn't found.
PROGRAMMERS: All new styles MUST go into this "standard" theme,
and the default colours should match the plain white look.
Once this theme settles down a bit we need to upgrade all the other
packaged themes accordingly.
