Update to ImgLib2 2.0.0-beta-10 + SCIFIO 0.5.0

This set of changes integrates the img-metadata changes in ImgLib2,
which rippled through SCIFIO as well. The work was done as a single
commit to avoid intermediate commits which break the build.
Merge branch 'img-metadata'

This branch updates ImageJ to use the ImgLib2 2.0.0-beta-10 release,
which features a restructured net.imglib2.meta package. It also updates
SCIFIO to 0.5.0, which is the corresponding version of SCIFIO using the
new ImgLib2 as well.
Change how AbstractData objects serialize axes