Implement order-preserving option forwarding.

Implement order-preserving option forwarding.

Needed to correctly handle things like 'llvmc -framework Foo foo.o -framework
Bar bar.o' - before this commit all '-framework' options would've been grouped
together in the beginning.

Due to our dependence on CommandLine this turned out to be a giant hack; we will
migrate away from CommandLine eventually.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96922 91177308-0d34-0410-b5e6-96231b3b80d8