Stubs for core/rpc/bitcoin-cli pages, new cyan theme

Began work on stub pages for the Core, RPC, and Bitcoin-CLI tutorial-page, as well as added cyan to the menu bar and changing the link color to white. (Still need to fix icon color and dropdown-background-color when in responsive (narrow) mode). 

Changed the dropdowns to better reflect our minimum-viable-product thoughts on first-pass of the content. Feel free to take these changes and begin adding your own content to them.


![pull request](https://f.cloud.github.com/assets/2126464/1426076/a47934e0-4057-11e3-9ee4-7c99315de38b.png)