support for npm webjars

[Odomontois]

I have following lines in build.sbt:

libraryDependencies += "org.webjars.npm" % "github-com-josdejong-jsoneditor" % "5.5.10"

libraryDependencies += "org.webjars" % "bootstrap" % "3.0.2"

and main.less as

@import "lib/github-com-josdejong-jsoneditor/soneditor.css";
@import "lib/bootstrap/less/bootstrap.less";

During LESS compilation content of second @import is successfully included in resulting main.css while first remains as declared

[mkurz]

Seems this should be working with version 1.5.0 with

• Add dependency on nodeModules #77

shipped.