Update README.md for new users and VIKit

Hi Jörg,

I would like to propose an update to README.md. It's ok if you want to reject this pull request :-)

To make it easier for new users to evaluate whether or not they want to use LabViewGitEnv, I have reordered the sections to have Usage and Quick Start first, followed by the full installation, configuration, and update instructions. I also added a reference to VIKit in the Quick Start and LabVIEW sections.

Finally, I also made a few minor spelling and formatting updates.

Since the file was reordered, the side-by-side diff is a little unclear. You can see the rendered version in my fork here: https://github.com/wireddown/LabViewGitEnv/blob/master/README.md

Joe