[GEN][ZH] Fix freeing reference-counted-pointer based memory leaks.

[Mauller]

Merge with Rebase

Fix freeing some reference counted pointers so that underlying memory is properly freed.

Will be checking for more so left this as draft for the moment.

Fixes:

• Gen + ZH - W3DLaserDraw was leaking materials.
• Gen + ZH - Production update was leaking production queue items if game exited before buildings sold or destroyed.
• ZH - Snow system was leaking on shutdown, wouldn't affect runtime but means a clean shutdown.
• Gen + ZH - W3DTankDraw was leaking particle systems, therefore leaking particles as well.
• Gen + ZH - MeshModel had an extra call to free directx8 references in the wrong place, this could cause other dependent assets to not be deallocated properly within reset(). And Generals behaviour was freeing data in the wrong order.
• Gen - Fix W3DWaypointBuffer not correctly handling it's materials internally, also matched and synchronised memory and initialisation related code changes to ZH. Resolved in another commit so removed other changes for now.
• Gen + ZH - Win32LocalFileSystem was leaking Win32File handlers due to creating a handler and returning early on a null filename before deleting it. Moved the creation of the file handler after the early return and where it is needed / used.
• Gen - MeshModel class was calling the wrong delete method when deallocating GapFiller data. Fixed already in ZH.
• Gen + ZH - Win32BigFileSystem was leaking Big32File handlers due to creating a handler and returning early on a null filename before deleting it. Moved the creation of the file handler after the early return and where it is needed / used.
• Gen + ZH - W3DDisplay was not releasing its debug display string so it could prevent DisplayStringManager from being cleanly destroyed.

[Mauller]

Small update, found that production items in a production queue could leak if there were production queues in progress.
This would happen if a game was exited or finished before the queue completed.

Selling or destroying the building appeared to deallocate the queue normally.

[Mauller]

Rebased with Main and added a new leak fix, Tank like vehicles were leaking particle systems when their W3DTankDraw object was destroyed.

[Mauller]

Small update where some references could be removed too early and some W3D asset manager glue was missing on mech models.

[Mauller]

Removed the MeshGeometryClass change as it was not necessary in the end.
Removed the W3DWaypoints change as i think the main thing i was originaly fixing in generals variant was fixed with a backport by Tomsons26.

The rest should be good to go now.

[tomsons26]

DisplayString instances may be leaking all over
neither m_benchmarkDisplayString or m_nativeDebugDisplay are even nulled in dtor..
m_displayStrings is just nulled but isn't deallocated..

assert( m_stringList == NULL ); will throw in DisplayStringManager DTOR if you play around with debug keys and exit game, appears to be m_benchmarkDisplayString instance it's holding on to as it contains "FPS 31.25"

[Mauller]

Rebased with Main after the recent inclusions. Just need to look at what Tomson26 found today.