impossible to install npm dependencies on a fresh system

[jansepke]

if you check out this repository and do a "npm install" you get errors like on this travis build of my pull request:

https://travis-ci.org/a8m/angular-filter/builds/71666732

PR #133

[a8m]

Thanks for reporting this issue @JanDalF .
Fixed via ed3b985
see: build-490