[author] Add less.js 1.7.2 and 1.7.3

Source:

https://github.com/less/less.js/blob/v1.7.2/dist/less-1.7.2.min.js
https://github.com/less/less.js/blob/v1.7.2/dist/less-1.7.2.js
and
https://github.com/less/less.js/blob/v1.7.3/dist/less-1.7.3.min.js
https://github.com/less/less.js/blob/v1.7.3/dist/less-1.7.3.js

Thanks