Add corrosion as a subdirectory, CMake fixes

Store all snowflakes in a separate array, achieving performance increase of about 10% for the whole engine on winter maps

Avoid creating unused string that is quite costly to produce

Improve pas2c rtl performance by avoiding double iteration on strings

Implement triggering advancement of simulation in qmlfrontend

Implement key bindings

Handle game view resize

Improve AI aiming with minigun

Wonder if anyone is trying to build this game anymore

Allow to move camera by dragging mouse cursor over game field

Fix build

Port QML frontend to Qt6, use rendering to framebuffer object

Start on adopting corrosion

Merge default

Fix type

sndCover now falls back to sndWatchThis OR sndFire. sndDrat and sndBugger now fall back to each other.

Fixed grammar, and reworded a few sentences to sound better.

fix early room deletion

fix room joining

thread server reference through dispatch to ensure rooms can be auto dropped

fix leaving rooms

fix rejoining

add some more buffer space

grow network buffer periodically

fix protocol recovery

merge the kick notice suppression

merge the lobby suppression

suppress this message too.

requested change by andu. filtering out ignored player. lobby notice

unc0rr commented this out in trunk. based on what andu reported it probably needs to be removed in the branch too