Update less.js to v1.6.3.

BS3 commits: ff2c506d2bd298e508bb4a36323c6eb42a30e679
Update dependencies.

BS3 commits: 2d18944d982a567b07b95d4b0719e7f85ff78e77
Add build-raw-files log; fixes 12603

BS3 commits: 7100e3a37eedf31f6ba005bb045ee3074a6ee5ed