Changing default 8-tap filter to Langrangian interpolator.

Changing default 8-tap filter to Langrangian interpolator.

The Lagrangian interpolation filter is maximally flat in the
passband. There is non-trivial improvement with the hd set, while
for derf the results are virtually unchanged.
See:
http://www.corp.google.com/~debargha/vp8_results/enhinterpn.html (derf)
http://www.corp.google.com/~debargha/vp8_results/enhinterpn_hd.html (HD)

Patch 2: Updated the results for derf in the html above to use the
new baseline. There is still about 4% improvement. Will update the
hd baseline later (since it takes 9 hours to run on my machine)

Patch 3: By mistake the default filter was left at 60 - should be 0
to use the new interpolation filter.

Change-Id: If5f64444976562415d68a2aeabb94fdfa0d47890