Pull request for new Landing Page, new Overviews, New 'new user' experience overall

Changed the landing page. Added a new image which was created based on the image you provided in one of the github issues. Moved a lot of the more verbose points to the "Overview" page. 

Renamed a couple tabs. Created new links on the top nav bar. 

Moved some content around (namely events and past projects being added to the Media page). Removed some redundant information on CAN off the Getting Started Page.

Added new verbiage on the Getting Started Page.

Created a "step-by-step Guide" which lists the steps users can follow to develop with OpenXC. This lists out and links to the individual pages and gives it an order users can follow to ensure they can start developing quickly.