add NestLoops to remove some uses of IVS

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@175303 91177308-0d34-0410-b5e6-96231b3b80d8
don't store a pointer to the loop in IVS

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@175304 91177308-0d34-0410-b5e6-96231b3b80d8
check that clang-format exists

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@175305 91177308-0d34-0410-b5e6-96231b3b80d8
capitalize SCEV to match the current naming convention

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@175306 91177308-0d34-0410-b5e6-96231b3b80d8