Rename rayrendsse to rayrendsse2
Restore default parameters for ibr ellipsoids
Optimizations for sse rayrend

- 'force' intel compiler to inline tiny sse wrapper functions
- unroll loop for trilinear interpolation and get rid of tmp[8] arrays
  (Couldn't find a better solution other than completely unrolling the
  loop for now, other strategies simply wouldn't result in unrolling on
  icpc, clang and g++. Unrolling results in a significant speedup on all
  platforms)
- reduce some overhead due to unnecessary sse::Vec() c'tor calls
- reduce some overhead due to unnecessary sse::Vec to sse::Veci conversions