v1.34.2: Reset to Default puts back a pane's configured links

A saved layout carries every pane's link configuration, and restoring one
replaces what the config gives the pane. A layout saved before an app
configured a link therefore switched that link off at every start -- and
layout.reset could not bring it back, because a reopening table went
back to its configured filters, sort and columns but kept whatever links
it had.

• A table whose pane reopens is back at the links its config gives it,
  as it is at its configured filters. So Layout > Reset to Default
  restores the configured links, and a save made after it stores them.
• A link added by hand from a header's Broadcast as... / Listen for...
  goes with a reset too: reset means back to the config.
• A restored layout still applies its own links after the reopen, and a
  closed pane shown again still gets back the links it was closed with.