Codechange: Replace pointer to Sprite array with reference to SpriteCollection. (#11580)

Add `SpriteLoader::SpriteCollection` type which is an array of `SpriteLoad::Sprite`.

This removes the ambiguity of what `SpriteLoader::Sprite *` is pointing to,
and cleans up mismatches using both dereference -> and array access [] for the
same object.

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

Fix #9804: Only apply sprite_zoom_min setting when sprites available (#9988)

Only discard sprite zoom levels when a suitable higher zoom level is
defined in the same colour mode

This is to avoid placeholder or empty sprites being used, causing
visual artefacts

(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 r10143) -Add: store the filename of the grfs opened and allow easy access to the name
-Codechange: store the SpriteID in the spritecache too
-Add: add a PNG loader for graphical files
-Documentation: added a document to explain the PNG format

(svn r10092) -Codechange: code-seperated the spriteloader and blitter from the rest of the code
-Add: make it possible to pick your own blitter (-b <blitter>, -h for overview)
-Add: added a new optimized 8bpp blitter (default, caches sprites of all zoom-levels)
-Add: added a debug 8bpp blitter and a very slow normal 8bpp blitter