Remove algorithms components

As discussed at the October 2014 ImgLib2 hackathon in Madison, they have
migrated to their own Git repositories:

* https://github.com/imglib/imglib2-algorithm
* https://github.com/imglib/imglib2-algorithm-fft
* https://github.com/imglib/imglib2-algorithm-gpl
Remove imglib2-meta component

It migrated into imagej-common. Source at:

https://github.com/imagej/imagej-common

As discussed at the October 2014 ImgLib2 hackathon in Madison, the
imglib2-meta component is being merged into imagej-common, because:

* It simplifies the dependency hierarchy of ImageJ2-based projects.
* It will facilitate simplification of the relevant class hierachies,
  particularly net.imglib2.meta.ImgPlus vs. net.imagej.Dataset.