Fixed gulpfile.js & package.json, now it works!

[alexshcer]

Problem:
The spectrogram project is not working.

Cause:
Some deprecated modules.

Fix:
Replaced/Updated some modules, and fixed the gulpfile.js and now it works!

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[alexshcer]

Modules Changed:
minifyCSS -> cleanCSS
jade -> pug

Modules Added:
vinyl-source-stream
vinyl-buffer