Remove: ZOOM_LVL_COUNT

This is the only enumeration with a COUNT and END. The logic of the COUNT
implied that BEGIN could be non-zero, but all but two uses of zoom level
assume that BEGIN is zero, making the separate count only confusing.

Codechange: automatic adding of _t to (u)int types, and WChar to char32_t

for i in `find src -type f|grep -v 3rdparty/fmt|grep -v 3rdparty/catch2|grep -v 3rdparty/opengl|grep -v stdafx.h`; do sed 's/uint16& /uint16 \&/g;s/int8\([ >*),;[]\)/int8_t\1/g;s/int16\([ >*),;[]\)/int16_t\1/g;s/int32\([ >*),;[]\)/int32_t\1/g;s/int64\([ >*),;[]\)/int64_t\1/g;s/ uint32(/ uint32_t(/g;s/_uint8_t/_uint8/;s/Uint8_t/Uint8/;s/ft_int64_t/ft_int64/g;s/uint64$/uint64_t/;s/WChar/char32_t/g;s/char32_t char32_t/char32_t WChar/' -i $i; done

Codechange: use IterateFromBack/Front only if the order is important.

Use Iterate if the order does not matter.

Fix: Apply master effect volume during mixing instead of sound start. (#8945)

This makes the volume control work as most players would expect, affecting
existing playing sounds as well as new sounds.

Codechange: Spell 'Viewport' consistently

Some places in the codebase misspell 'Viewport' as 'ViewPort' or 'view_port'.
This patch makes everything consistent.

(svn r12169) -Change [FS#1696]: play sounds when there is only small part of tile/vehicle visible too (original idea by Dominik)
It improves the game appearance when playing with very small screen resolution

(svn r11095) -Codechange: don't abuse 'file_pos' by storing the file_slot in it too, but use a nice seperate variable for it
-Note: on a side-note, this allows files bigger than 16+ MiB, needed for tar-support

(svn r9885) -Fix r9846: some last bitshifts with zoom-levels that were forgotten
-Fix r9846: initialize the zoom level for 'screen', as assuming 0 is not correct

(svn r9846) -Codechange: introduced ZOOM_LVL_MIN and ZOOM_LVL_MAX for the obvious reasons
-Codechange: introduced ZOOM_LVL_DETAIL to show/remove details
-Codechange: changed << and >> operator with ZoomLevel to a simple wrapper (that in theory also allows zoom-in besides the current zoom-out)
-Fix r9845: missed some int -> ZoomLevel