Update ninja to v1.7.0 on Mac, Linux32, Linux64, Windows.

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

The linux binaries were built by thestig@chromium.org.
The windows and mac binaries were built by thakis@chromium.org.

The Windows binary is now 64-bit instead of 32-bit.

BUG=607268
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/1919773006 .

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300251 0039d316-1c4b-4281-b951-d872f2087c98