oxygen icon name clasheroo

[Harald Sitter]

Hola!

Our most awesome icon maintainers wanted to carry over icon symlinking
from breeze to oxygen, alas that turned up a whole slew of
compatibility problems.

examples:
https://bugs.kde.org/show_bug.cgi?id=360605
https://bugs.kde.org/show_bug.cgi?id=360510

# Problem
In kde4 software people used oxygen as the standard icon set and
installed their own icons there. Since breeze covers all icons ever,
replicating its coverage into oxygen means we have a million conflicts
with (older?) tarballs of existing software that also install icons
into oxygen under the same name.

# Proposal
We could get rid of this and all future conflicts if we shift the
default oxygen icons into a subdirectory.

So, we install the default icons to

$prefix/share/icons/oxygen/base/22x22
$prefix/share/icons/oxygen/base/32x32
$prefix/share/icons/oxygen/base/...

applications can thus continue to install to

$prefix/share/icons/oxygen/22x22
$prefix/share/icons/oxygen/32x32
$prefix/share/icons/oxygen/...

without conflicting with our base files what so ever.

Downside of this is that the index.theme basically needs to list
everything twice (once for base and once for main directory), which
unfortunately incurs a bit of a runtime overhead. This is a bit of a
crap situation we are in and I can't think of another solution to
this.

Input welcome

HS