Make attached meshes use their own blit parameters (#1095)

This might break some scenarios which for example change the color modulation
of a clonk and then expect that also its shovel or other objects get colored.
Such scenarios need to be fixed by also coloring the attached objects. This
might not be very convenient, and maybe we should introduce an option for
attached meshes to use the old behaviour (take blit parameters from main
object).

However, let's see how this change turns out in practise and then we see
whether further modifications are needed.
Allow distributions to use the system tinyxml.

Add a new cmake option WITH_SYSTEM_TINYXML=ON that allows to use the system
tinyxml library and header instead of the bundled copy. Adjust the include
path in the single source file referencing the header and add the thirdparty
path to the include search path if the use system option is unset or off.
Fix thread guards to use thread IDs instead of handles (#1161)

GetCurrentThread() returns the same pseudo-handle for every thread. It cannot be used to determine if two calls were made from the same thread.
Fix pixel masks Solid/Liquid/Background in map scripts.

Solid/Liquid/Background depend on PixMaps in C4Landscape being updated to currently loaded materials.

PixMaps should really be functions of C4MaterialMap and C4TextureMap. It's probably still broken in mape.
mape: use global texture map

Otherwise certain script functions would only access an empty texture map
mape: initialize the landscape pixmaps (#1162)
Remove debug logs
Add explosive mode for rockfall.

Makes it a bit more deadly by blasting through rock and granite.
Make gems non-corrodable.

It's annoying in acid gem mining scenarios.
New world: Acid Rift.
Fix nil pointer if a dragged object is deleted between control creation and control execution.
added object name to menu item tooltips (#1146)
increased chest content count and make cabin non-enterable (#1159)
fixed underwater dropping of second hand item (#1155)
fixed cloud movement in ironpeak(#1149)
add test scenario for power system
improved smoke for some structures
removed cloud vertices
correct difficulty for acid rift
allow to cut the pump's source and drain (#1144)