Codechange: Store text run positions in vector of points.

This simplifies the interlaced vector of x/y positions.

Fix #11485: new run on same line must not use last_space of previous run as cut-off point

Use the start of the next run instead as the location of the last space.

Codechange: Use std::vector in fallback layouter, and shorten accessors. (#11355)

This avoids use of malloc/free (and custom move constructors), and follows how the exist layouters are written.

Codechange: All ParagraphLayoutFactory::AppendToBuffer assume that the buffer has at least some space.
Assert on that.

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

Feature: drop ICU-lx in favour of directly interfacing with harfbuzz

This means we have RTL support again with ICU 58+. It makes use of:
- ICU for bidi-itemization
- ICU for script-itemization
- OpenTTD for style-itemization
- harfbuzz for shaping