Many changes

* Simplify a lot of the inlining stuff.  There are still problems, but not
  many
* Break up the Function representation to have a vector for every different
  node type so it is fast to find nodes of a particular flavor.
* Do more intelligent merging of call values
* Allow elimination of unreachable shadow and allocation nodes
* Generalize indistinguishability testing to allow merging of identical calls.
* Increase shadow node merging power

llvm-svn: 2010