Less: Remove empty lines and blanks.
Update dev dependencies.
Update Ruby dependencies.
Merge pull request #14458 from twbs/npm-deps

Update dev dependencies.
Merge pull request #14453 from vsn4ik/less_empty_lines

Less: Remove empty lines and blanks.
Update Blob.js to v2014-07-24.
Filesaver.js v2014-07-25.
Update JSZip to v2.4.0.
Update Holder.js to v2.4.0.
Update less.js to v1.7.4.
Run `grunt`.