Change page.goto to page.setContent

• Fix bugs caused by the newer version of puppeteer #12 #13 #14 #15.
• Better documentation.
• npm script for running the examples.

Add Puppeteer options

Add #7 - Adding the option to launch puppeteer with custom options received through options parameter in generatePdf.

Docs update and a bug fix

• Re-ordered the examples folder, and added another example.
• Updated the readme to help avoid issue #1