Fixing whitespace in maven dependencies xml

Fix mirror/credential application within MavenPomDownloader and add t…

…est for it

Fix RemoveImport to not see method invocation identifiers as referenc…

…ed fields

Update README.md

BlankLinesVisitor supports formatting a statement according to the in…

…dentation of an empty class body

Ensure sources jars get generated so hopefully bintray will let us pu…

…lbish again

Standardize maven continueOnError behavior. Add onError handler. Remo…

…ve slf4j api usage

Handle continue-on-error for a few more possible failures in Maven pa…

…rsing openrewrite#199

Catch and suppress another possible error in RawMavenResolver openrew…

…rite#199

Extend continueOnError functionality to dependencyManagement openrewr…

…ite#199