Import once

[nielsAD]

Import files once as proposed by @Ysor in issue #396.

[stof]

@import should not import only once. Less 1.4 has an @import-once feature for this.

[akomm]

Check this:
less/less.js#212
and this:
#396

Quote:
Continue to support @import-once for backwards compatibility.
In: #396

Its only for backward compatibility