mem.Dynamic_Pool feels misnamed

[Beefster09]

I started using this thinking that this was a pool allocator - i.e. an allocator that operates on equal-size chunks of memory, but as it turns out from what I can see in the source, it seems this is more like a growable arena allocator, but it's not even ideal as a temp allocator because its free_all operation actually frees all blocks instead of just resetting the pool.

I propose that the struct and associated procs should be renamed to Dynamic_Arena or something along those lines.

[flysand7]

#4209 Adresses this

[flysand7]

The Dynamic Pool is indeed a misnomer. For now the proposed solution is to rename it to dynamic arena, but keep the old aliases for a while.