Changes "Exchanges" to "Get Dogecoin" in Buttons, Adds Buttons to Getting Started guide.

This Pull Request provides more information to newcomers and newbies. It changes "Exchanges" to "Get Dogecoin" in the buttons on the bottom of the homepage.
Before (Exchanges): http://puu.sh/8p6rn
After (Get Dogecoin): http://puu.sh/8p6s6

I also retyped the modal.
http://puu.sh/8p6EO

In the Getting Started guide, it now has buttons! This is so they know what to do after they set up their wallets.
Buttons in Getting Started Guide: http://puu.sh/8p6oJ