Improvements

Again, there's several things going on in this pull request:
1. Addressing all of the issues brought up with the getting started page in the last PR (https://github.com/DevOpsBootcamp/website/pull/52)
2. Improving the "attendance" section of "policies" according to discussion had at last bootcamp meeting (https://github.com/DevOpsBootcamp/website/issues/53)
3. Changing Bootcamp to BootCamp -- Rachel brought this up as something that was incorrect and which really bothered her.
4. Rearranging What is devops, mission statement, and purpose of devops, as at this point these are three very similar ideas which can be on just one page on the site.
5. Moving more data above the fold. I tried to add social media links, and frankly they looked terrible, so I'm going to try to do something more creative.  PR to follow. 

@jordane @edunham @iankronquist @ElijahCaine  I'll wait for +1's from at least two people -- I know that there are lots of changes to be made to the site, so this is really just a starting point, not all the changes we'll be making.  Let me know if you see any errors, or things which you think should be different!
Just to be sure, I'm only removing the CentOS box, yes?  They still need vagrant and virtualbox in order to run the vagrantfile.