tree 3fff1e7fc6c63777d7821c26feec5ee48e873b51
parent f217ccfb6946d8b8f1a9aff1061213f153f65f78
author Mike Vitus <vitus@google.com> 1519324119 -0800
committer Mike Vitus <vitus@google.com> 1519670273 -0800

Adds a Ceres Context structure.

A Ceres Context holds common global state that can be re-used within
Ceres.  The Context current contains a thread pool if compiling with
C++11 threading support.  Threads are expensive to create and destroy so
it is good to maintain across multiple Ceres solves.

Tested by compiling with and without TBB support and ran unit tests. Ran
bazel as well.

Change-Id: I82f598dfae642aa0e81a6039dc174608a5e8dbfb