Fix and refactor gulp for branch v1.5#36

dunkelziffer wants to merge 2 commits intolarspetrus:v1.5larspetrus/Roofpig:v1.5from

dunkelziffer:kw/gulp_v1.5/30-gulp-build-doesnt-workdunkelziffer/Roofpig:kw/gulp_v1.5/30-gulp-build-doesnt-workCopy head branch name to clipboard