incremented version in pom.xml and README.md
fixed README
and another quick update.
adding -SNAPSHOT back for maven-release-plugin
fixed Maven build warnings
changed scm url
[maven-release-plugin] prepare release xchart-1.2.1
adding -SNAPSHOT back for maven-release-plugin
[maven-release-plugin] prepare release 1.2.1
[maven-release-plugin] prepare for next development iteration