POM: use tabs instead of spaces
POM: fix groupId and version

This is a SCIFIO project, and needs to have groupId io.scif.

And we *definitely* want the version to be set to a SNAPSHOT.
Otherwise there will be multiple POM variants stored in the SCM,
all with release version 1.0.0, which is illegal.
POM: use pom-scijava, not pom-loci
POM: fix dependencies
POM: remove unneeded .git suffixes
POM: simplify repositories block