Update qs dependency

See https://blog.liftsecurity.io/2014/08/06/denial-of-service-in-qs and https://nodesecurity.io/advisories/qs_dos_extended_event_loop_blocking

```sh
$ git clone https://github.com/missinglink/ciao.git ciao
$ npm install

$ npm shrinkwrap --dev
wrote npm-shrinkwrap.json

# $ sudo npm i nsp -g
$ nsp audit-shrinkwrap --no-color

Name  Installed  Patched  Vulnerable Dependency
qs      0.5.6     >= 1.x  ciao
qs      0.5.6     >= 1.x  ciao

$ npm outdated --depth 0
Package        Current  Wanted  Latest  Location
walk             2.2.1   2.2.1   2.3.3  walk
coffee-script    1.6.3   1.6.3   1.7.1  coffee-script
mkdirp           0.3.5   0.3.5   0.5.0  mkdirp
should           1.2.2   1.2.2   4.0.4  should
async           0.1.22  0.1.22   0.9.0  async
winston          0.6.2   0.6.2   0.7.3  winston
qs               0.5.6   0.5.6   1.2.2  qs
cheerio         0.10.8  0.10.8  0.17.0  cheerio
```