add area_overlap method for apertures (#874)
add area_overlap method for apertures (#874)

* add area_overlap method for apertures

* speed up area_overlap by using only one list comprehension

* correct return type of area_overlap

* only create array of ones once

Co-authored-by: Larry Bradley <3525f6f7ce7c72c42b76270c4632e20d8dd23665@gmail.com>
larrybradley/photutils,astropy/photutils