The new WebM output support should be preferred to IVF, but we can't
change the default behavior of the ivf* tools. There are a few other
default behaviors for these tools that are counterintuitive for
historical reasons, and changing the binary name provides the
opportunity to clean those up as well. This patch takes the first
step by renaming the binaries.

Change-Id: I647008ae37cc352dd27ec1da7ed13489e0609b24