Code comments for divides_array. Fix a few minor bugs.
Code comments for divides_array. Fix a few minor bugs.

wbhart/flint2,wbhart/flint2,dsroche/flint2,fredrik-johansson/flint2,fredrik-johansson/flint2,wbhart/flint2,fredrik-johansson/flint2,dsroche/flint2,dsroche/flint2,dsroche/flint2