Force empty/ones/zeros_like() to copy mask

As underlying `empty_like()` knows nothing about mask, it would be
`_convert2ma`'s job to properly set up the output mask. `copy` argument
is added to figure out which functions need this behavior.

`ones_like()` and `zeros_like()` which were mere aliases of regular
numpy functions now go through `_convert2ma` as well.

Hopefully this fixes #3145, #2572.