fixes #265: add semver validation checks to non-bundle builds
bump maven-enforcer to 1.3.1 and remove some xml cruft
Merge branch 'master' of github.com:Parquet/parquet-mr into add_semver_checks
ignore jackson packaging changes w.r.t semver
add maven central as a repo to work around Travis build issues with semver
remove snapshots=false from maven central xml
Force <previousVersion>

Signed-off-by: Chris Aniszczyk <zx@twitter.com>
Merge pull request #268 from Parquet/add_semver_checks

fixes #265: add semver validation checks to non-bundle builds