Add SSE code to columnar scan

[githubmanticore]

Some places in MCL code were intended to be written in SSE (and marked as such in comments), but were temporarily implemented in plain instructions. This needs to be fixed in order to improve search performance over columnar attributes.

[githubmanticore]

➤ Ilya Kuznetsov commented:

Done in 207ab42. Queries like SELECT count(*) FROM taxi WHERE trip_type=0; became 5% faster.