CONTACTS status flags:
	(there is no flag "preContacts")
	currentView = makePreContactsSpt() // use match()
		markContactsTargets true
		selectMode c=Chains, g=Residue, etc. BECOMES BLANK when contactsShowing=true
	contactsShowing true/false
	currentView = makeContactsShowingSpt()
		labelContacts

---------------
the view link stores
	makePreContactsSpt() and makePreContactsHelp()

When the view link is clicked both of the above are executed by
---------
doViewLink() which before executing them

	if contacts are already showing (preContacts local to doViewLink())
	  confirms starting over

	if the new view is unrelated (not one to modify contacts e.g. find,
	hide, center, or a harmless one, e.g. more views or troubleshooting)
	then
    contactsShowing = false;
    markContactsTargets = false;

	if we are doing preContacts, resetContacts() which must be done
	before showing help.

	SHOWS HELP
	executes and shows makePreContactsHelp() (done before the script)
		if selectMode == "", clearSelectedArrays() and selectMode = "c".

	sets contactsView = "sf"

  clearSelectedArrays();
  spt += "select none; define ~targ_current selected;\n";

	DOES THE SCRIPT
	finally doMolViewSpt(makePreContactsSpt())
----------------------------
doMolViewSpt() in scripts.js (for preContacts)

does several things unrelated to contacts

then calls ScriptToJmol() (top.js)

does makeMarkContactsTargetSpt()

then unchangedScriptToJmol() (top.js)
----------------------------
makePreContactsSpt()
does not change any settings
----------------------------
The final view is done with
makeGenerateContactsSpt()
which clears hidden and then does
  makeDefineContactsSpt() + makeContactsViewSpt()
		all in scripts.js

	makeContactsViewSpt() uses bond-type checkboxes to select each checked category setting
		~cont_targ and ~cont_current (balled atoms)

redisplays anything hidden during contact target selection with clearHidden().