docs: Sphinx conversion is "done"

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171375 91177308-0d34-0410-b5e6-96231b3b80d8
docs: Decrease toctree depth on landing page.

Having the table of contents there was making it hard to easily see at a
glance all the docs we have.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171376 91177308-0d34-0410-b5e6-96231b3b80d8
docs: Change title.

The core of this page is a set of pros/cons for the different ways to
use clang as a library. The title should reflect that the page helps you
choose between alternatives.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171377 91177308-0d34-0410-b5e6-96231b3b80d8
remove random spaces

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171378 91177308-0d34-0410-b5e6-96231b3b80d8
docs: Reorganize landing page.

I clustered the docs by some intuitive/fuzzy notion of "similarity", and
some reasonable categories seemed to materialize. I tried to give the
clusters useful names, but you may want to take a look at the landing
page (<http://clang.llvm.org/docs/> for the lazy) and share your
thoughts.

I have to say, this small change really gives the docs a whole new life!
It makes our documentation quite a bit easier to navigate and scope out.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171379 91177308-0d34-0410-b5e6-96231b3b80d8