REF: use unpack_zerodim_and_defer on EA methods
@jbrockmendel I am +1 on this, can you merge master. If @jorisvandenbossche object to the array/base.py impl then ok but otherwise lgtm. can u rebase and add the suggested test Mothballing I reopened this because I think it are useful changes. I only changed it back in the base implementation (which is not used in pandas), as I suggested above. 
@jbrockmendel are you fine with merging it like this? @jorisvandenbossche i just rebased and force-pushed, might have undone the commit you pushed.  feel free to re-do that I forced pushed again my branch, but it still needs a merge of master. And also merged master lgtm. @jorisvandenbossche merge when ready. (or ping and i will)