Remove another extra comma

Conflicts:
	app/views/tree_display/_page_footer.html.erb
Remove extra comma

Conflicts:
	app/views/tree_display/index.html.erb
Replace use of instance variables with local variables.

Also introduce additional local variables to fix selected fields remaining selecte (previously
the instance variables they used were never set)

Conflicts:
	app/views/tree_display/_page_footer.html.erb
	app/views/tree_display/index.html.erb