Merge pull request #6 from lrobertson39/master

[JENKINS-19907] fixed
add groovy script functionality
Merge branch 'master' of github.com:jenkinsci/extended-choice-parameter-plugin
[maven-release-plugin] prepare release extended-choice-parameter-0.31
[maven-release-plugin] prepare for next development iteration
Fix regressions in recent release

1. Use JSONObject optInt() instead of getInt() to handle null value or
if value is not a number.
2. Value for Property Value not loaded from config file.