* Cnstants are now global objects

* Cnstants are now global objects
* ConstantPools no longer exist
* Constants are global objects in the LLVM system
* Constants are structurally equilivant if they are pointer equilivant
* Support abstract & opaque types
* Support setName on constants even though they don't track names
* Constnats don't get copy ctors anymore
* ConstPoolVal::equals is no longer useful [use ptr equivalency]
* Support generic factory classes to create and maintain constants

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@460 91177308-0d34-0410-b5e6-96231b3b80d8