Option "Skip terms without enabled menu item" was removed,
because now we select from menu items only, not terms.

New behavior guarantees menu item existence without extra
DB query, because we're using menu item from selection
to set it as preferred link.

Almost complete rewrite. Settings are now integrated with
node type edit form and field edit form. Selection methods
"Last/First with menu" moved to separate option "Skip
terms without menu item". Still missing Taxonomy Menu
integration (if it is still needed) and "Deepest in lineage"
selection method and full of TODOs and bugs.

#970714 by maximpodorov: Vocabulary selection was not used by term selection methods other than "Deepest in lineage"

by Dmitriy.trt: New "Deepest in lineage" term selection method. Selectable vocabularies for each content type to select terms from

#935952 by xgmorkx: Fixed server hangup on nodes with terms when none of theese terms have menu items and term selection method was set to "First term with menu" or "Last term with menu"