speeding up `npm install` by disabling the progress bar

gistfile1.txt

with `react-native`:

npm set progress=false && rm -rf ~/.npm && rm -rf node_modules && npm cache clean && time npm install
npm install  83.72s user 26.03s system 100% cpu 1:49.32 total

npm set progress=true && rm -rf ~/.npm && rm -rf node_modules && npm cache clean && time npm install
npm install  199.30s user 27.32s system 91% cpu 4:08.29 total

--

npm set progress=false && rm -rf ~/.npm && rm -rf node_modules && time npm install
npm install  70.27s user 22.12s system 120% cpu 1:16.85 total

npm set progress=true && rm -rf ~/.npm && rm -rf node_modules && time npm install
npm install  202.59s user 26.47s system 105% cpu 3:36.52 total

$ node -v
> 5.3.0
$ npm -v 
> 3.3.12

# with progress
npm install  110.43s user 15.62s system 33% cpu 6:13.81 total
# without progress
npm install  51.30s user 14.00s system 22% cpu 4:56.09 total

(master ✓)❯ node -v
v5.3.0
(master ✓)❯ npm -v
3.3.12
# with progress
npm install  65.97s user 4.15s system 35% cpu 3:16.78 total
# without progress
npm install  41.70s user 3.77s system 25% cpu 2:56.22 total