Install Maven 3.1.0 with community cookbook v1.0.0

This mature version of http://community.opscode.com/cookbooks/maven
is now able to satisfy Travis CI requirements.

Maven is thus (again) installed from Apache tarball releases, which
offers better flexibility compared to Ubuntu packages.

Close travis-ci/travis-ci#1324
Shift MAVEN_OPTS to global settings (/etc/mavenrc)
Merge pull request #229 from gildegoma/maven-3.1.0

Install Maven 3.1.0