[BumpPtrAllocator] Move DefaultSlabAllocator to a member of BumpPtrAllocator, instead of a static variable.

The problem with having DefaultSlabAllocator being a global static is that it is undefined if BumpPtrAllocator
will be usable during global initialization because it is not guaranteed that DefaultSlabAllocator will be
initialized before BumpPtrAllocator is created and used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189433 91177308-0d34-0410-b5e6-96231b3b80d8
cmake: Add msbuild integration to the install

This adds the msbuild integration files to the install, provides batch scripts
for (un)installing it in a convenient way, and hooks up the nsis installer to
run those scripts.

Differential Revision: http://llvm-reviews.chandlerc.com/D1537

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189434 91177308-0d34-0410-b5e6-96231b3b80d8