More uniform function names for heaps

[markuspf]

We should probably use uniform names for the heap-api functions such as BinaryHeap_Push and PairingHeap_Push (and by extension WhateverHeap_Push).

[fingolfin]

Are these really APIs? Or rather: Do we want those to be APIs? To me, they are implementation details, which the user should not access directly.
The one reason I can think of why one might want to change that is because by making them "official", the user can conveniently bypass method dispatch. That convenience is, however, bought with us being forced to keep supporting these names indefinitely.

I'd tend to default to not doing that, and wait until somebody show us a usecase where (a) method dispatch causes a noticeable and relevant speed penalty, and (b) "manually" retrieving and using the applicable methods, using ApplicableMethods, for some reason is not a (good) solution...