setting java.version property to 1.8 is no longer required, as it is already included in the spring-boot-starter-parent pom.xml as of 2.0.0 release.

Fixes gh-32

The link to see the spring boot starters source code in GitHub leads to the wrong page showing the 404 page. I updated the link to  go to the actual page that shows the code for spring boot starts

At the bottom of the document (above the footer), I added links to other guides that readers may find to be useful.

Resolves #30