Improving the "Getting started" block

Currently when installation OpenScholar there's hardly any information on how to setup a VSite, or the _main_ site's [front page](https://github.com/openscholar/openscholar/wiki/Adding-widgets-to-the-sitewide-frontpage). The PR is about adding some initial help. 

#4410 

I improved a little bit the getting started so it could fit to the issue.

Inside a vsite:
![get 2](https://f.cloud.github.com/assets/1222368/1521798/e097649e-4b9a-11e3-9074-80e046da19e1.png)
![get](https://f.cloud.github.com/assets/1222368/1521799/e31db010-4b9a-11e3-8ca2-e46fcf08ff84.png)

outside the vsite:
![get 3](https://f.cloud.github.com/assets/1222368/1521801/e6a581f4-4b9a-11e3-8569-2f0ed69f604a.png)
![get 4](https://f.cloud.github.com/assets/1222368/1521802/e8b67f48-4b9a-11e3-9891-bff83b089e9b.png)