Codechange: Remove direct access to _colour_gradient.

Access is now through GetColourGradient, which ensures parameters are in range.

Codechange: Make all NWidgetPart arrays constexpr.

This ensures that the arrays are not created at runtime and prevents using non-constexpr values.

Codechange: Replace mishmash of types for widget index with WidgetID.

Indices were stored as int, but often passed around as uint/uint8_t and casts.

Now they should all use WidgetID.

Codechange: Remove FONT_HEIGHT_... macros. (#11481)

These make it look like we're dealing with a constant, but actually each is a call to `GetCharacterHeight(...)`.

Codechange: Add __FILE__/__LINE__ of WindowDesc to WindowDesc.

This is to allow unit-tests to produce more useful output.

Add: data parameter in Window::Close method.

This allows passing data when closing a window, e.g. to indicate how it was closed.

Codechange: Use begin/end of nwidget parts of begin/length.

This simplifies processing nwidget parts as, unlike the remaining length, the pointer to the end of the list never changes. This is the same principle as we use(d) for tracking end instead of length for C-style strings.

And this removes 160~ instances of the lengthof() macro.

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 #10987: Double-close of dropdown stopped land-info tool working as default. (#11000)

Clicking and releasing on the query toolbar icon is meant to select the land-info tool.

This did not work as during closing a window, OnFocusLost() is called, which then closes the window again. These two calls toggled the land-info tool one and off in the same action.

Resolve by not calling Window::Close in OnFocusLost() if the window is already closing.

Codechange: C++-ify the Layouter and related functions

They all now access a std::string_view, instead of a "const char *"
or std::string (in some cases).

Additionally, GetCharAtPosition and friends now return an index
instead of a "const char *", as it makes for a more clear interface.

Change: include fmt.h C++ headers in stdafx.h

This to prevent compilation issues between runs with and without precompiled
headers. Also remove the headers from the rest of the code base as they are
not needed there anymore, although they do relatively little harm.

Codechange: migrate all Window-related timers to the new framework

This means we also say goodbye to GUITimers.

Codechange: replace IConsolePrintF with IConsolePrint and fmt formatting

Also make some strings more consistent with the rest of the console strings.