#5335 Use covariant return types on virtual Grob::clone()

[Dan Eble]

Use covariant return types on virtual Grob::clone()

... and remove unnecessary dynamic_casts.

The casts in the parser were not Grob-related, but since they turned
up during my search, I removed them too.

http://codereview.appspot.com/341320043

[Dan Eble]

fix style

http://codereview.appspot.com/341320043

[Anonymous]

Passes make, make check and a full make doc

[Anonymous]

Patch on countdown for June 10th

[Anonymous]

Patch counted down - please push.

[Dan Eble]

commit 23534338bce94508ddbfbbbd4a746619eb403fd5 (HEAD -> pushed/issue-5335-grob-clone-covariance, origin/staging)
Author: Dan Eble nine.fierce.ballads@gmail.com
Date: Sun Jun 3 19:23:14 2018 -0400

Issue 5335/2: Remove other unnecessary dynamic_casts
unrelated to the previous commit

commit 2164bfe5d73b9a660627f43c001ea69453680d68
Author: Dan Eble nine.fierce.ballads@gmail.com
Date: Sun Jun 3 18:30:17 2018 -0400

Issue 5335/1: Use covariant return types on virtual Grob::clone()
and remove unnecessary dynamic_casts.