swift234

Rework the selector-splitting heuristics.

This makes a number of changes to the selector-splitting
heuristics. Specifically:

  - Eliminate last-word splitting, and with it the notion of
    multi-words. We only split at prepositions now.
  - Introduce the notion of "linking verbs" such as "will" or
    "should"; when these show up, we refuse to split a selector, which
    helps with delegates.
  - Eliminate the special case for "get" and "set". It wasn't
    helping.
  




Swift SVN r16265