Updating maven to 6.3.1 for new release

git-svn-id: http://libphonenumber.googlecode.com/svn/trunk@709 ee073f10-1060-11df-b6a4-87a95322a99c
[maven-release-plugin] prepare release libphonenumber-6.3.1

git-svn-id: http://libphonenumber.googlecode.com/svn/trunk@710 ee073f10-1060-11df-b6a4-87a95322a99c
[maven-release-plugin] prepare for next development iteration

git-svn-id: http://libphonenumber.googlecode.com/svn/trunk@712 ee073f10-1060-11df-b6a4-87a95322a99c