Evaluate Checkstyle for analysing good code layout

[llewelld]

Also helpfully suggested by @brett-lempereur, Checkstyle could be useful for checking coding style: "Similar to PMD, but more focused on aesthetic aspects, it doesn’t include all of PMD’s features but probably does some things that PMD doesn’t."

Checkstyle: http://checkstyle.sourceforge.net

This could possibly be used to replace the current indentation, variable and comment checks.