Remove warning logs on Travis

[mdelapenya]

> npm install && ./node_modules/.bin/webpack --config ./webpack.config.js
npm WARN package.json [secure][email protected] license should be a valid SPDX license expression
-npm WARN engine [email protected]: wanted: {"node":">=4.3.0 < 5.0.0 || >= 5.10"} (current: {"node":"4.1.2","npm":"2.14.4"})
npm WARN engine [email protected]: wanted: {"node":">=4.7"} (current: {"node":"4.1.2","npm":"2.14.4"})
npm WARN engine [email protected]: wanted: {"node":">=4.3.0 <5.0.0 || >=5.10"} (current: {"node":"4.1.2","npm":"2.14.4"})
npm WARN peerDependencies The peer dependency file-loader@* included from url-loader will no
npm WARN peerDependencies longer be automatically installed to fulfill the peerDependency 
npm WARN peerDependencies in npm 3+. Your application will need to depend on it explicitly.
-npm WARN optional dep failed, continuing [email protected]
-npm WARN engine [email protected]: wanted: {"node":">=4.3.0 <5.0.0 || >=5.10"} (current: {"node":"4.1.2","npm":"2.14.4"})
npm WARN engine [email protected]: wanted: {"node":">=4.3.0 <5.0.0 || >=5.10"} (current: {"node":"4.1.2","npm":"2.14.4"})
-npm WARN optional dep failed, continuing [email protected]
-> [email protected] install /home/travis/build/craftsmanship-toledo/[secure]pp-frontend/node_modules/node-sass
> node scripts/install.js

[mdelapenya]

Many of them have been fixed:

npm WARN prefer global [email protected] should be installed with -g
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@^1.0.0 (node_modules/chokidar/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN [email protected] requires a peer of file-loader@* but none was installed.
npm WARN [email protected] license should be a valid SPDX license expression