Update README.md

Added description for 0.13.0 as well.
Updated scalastyle-config.xml with latest config from scalastyle

Used the contents from https://github.com/scalastyle/scalastyle/blob/scalastyle_2.10-0.3.2/src/main/resources/default_config.xml

Several new rules have been included (ex. BlockImportChecker)
Merge pull request #9 from diwa/patch-1

Updated scalastyle-config.xml with latest config from scalastyle