Update Ceres to current HEAD

Brings up some noticeable speed improvements. In particular
the automatic differentiation and bundle adjustment solvers.
 Bundle adjustment improvements

- Get rid of rotation matrix parameterization,
  use angle-axis instead.

  Also Joined rotation and translation into
  a single parameter block.

  This made minimization go significantly faster,
  like 1.3x times in average.

- Fix first camera when bundling. This is to
  address orientation ambiguity.

  Reconstruction result could still vary in
  size, but that's another issue to be addressed
  later.

Additional change:

Split EuclideanBundleCommonIntrinsics into
smaller functions, so it's now a bit easier
to follow.