Changeset a6401ff3 in git

Improve handling of hidden splay ends

Previously, hidden splay ends still served as "targets" for snapping
the mouse pointer to, and still got crosses when crosses were
enabled.

We don't have a handy flag for "this is the outer end of a splay"
and computing that on demand isn't so easy to do, so for now we
use the "anonymous station" flag so at least these cases now behave
properly for splays to anonymous stations (which is likely to be
what people with huge numbers of splays from disto-x, etc are
using). This does mean that anonymous stations on continuation
passages will incorrectly also be off when splays are hidden, but
that seems an OK trade-off for now.

The snapping of the mouse pointer was reported by Frank Tully in #105.