Update ninja to v1.7.1 on Mac, Linux32, Linux64, Windows.

See the bug for how these were built (comment 16 onwards).
See the bug comment 0 also for what's new in this version.

All binaries built by thakis@chromium.org.

The Windows binary is now (as of 1.7.x)  64-bit instead of 32-bit.

BUG=607268
TBR=scottmg@chromium.org

Review URL: https://codereview.chromium.org/1925133002 .

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300281 0039d316-1c4b-4281-b951-d872f2087c98