Create pdfkit.rb
Add commented out require for Windows pdfkit config
Add note to README regarding wkhtmltopdf on Windows
Change wkhtmltopdf path to a path without spaces
Update wkhtmltopdf for Windows note in README

The wkhtmltopdf path should not contain spaces for pdfkit to work.
Merge pull request #3 from mhenry07/feature/wkhtmltopdf-windows

Add notes and configuration for wkhtmltopdf on Windows