Adds grunt tasks for PDF generation

Adds tasks to generate a PDF from openreferral.md markdown. The
generated PDF appears in ./pdf/ and includes the git commit ID in the
filename.
Updates Readme

Updates Readme to include PDF generation instructions.
Converts spaces to tabs
Updates Readme

Adjusts Readme formatting.
Merge pull request #33 from codeforamerica/auto-pdf-gen

Markdown to PDF generation