I don't know what I was thinking when I added
bbce11c, but it is possible to have
palettes with fewer than 256 colours and no header. None of the games I
checked seem to use this format, so it's gone for now.

Fixes palette loader for Pothead.

b_member will return a CASTREF as long as the member ID is within range
for that cast library; that is, less than or equal to the highest member
ID. It does not check that the cast member exists.

Fixes loading sequence of Gothos.

Turns out the criteria was a bit different. the result does work with
recursive calls, the capture criteria is if the returned value
is otherwise discarded.

Fixes director-tests/D4-unit/T_LING03.DIR
Fixes sound playback in Pothead.

The output is expected to use line/character positioning instead of
row/column positioning; so if a line of text spans multiple rows, it
should be handled normally.

Fixes selecting inventory items after "Ptn of Random Teleport" in Derrat Sorcerum.

Fixes the dot-to-dot puzzle in Interactive Bible for Kids: The Life of Paul

Fixes talking to the barmaid in Derrat Sorcerum.

Apparently this is also used for for constraint checks.

Fixes mouse code in the Barber Joe minigame of Rodney's Funscreen.

Director reads until the end of the line after "then" and sets the Lingo
event handler to that expression. This could be a newline immediately
after "then".

Fixes script execution in the Barber Joe minigame of Rodney's Funscreen.

The manual implies that this property is only used by buttons, but it is
a boolean property that you can get and set on any cast member type.

Fixes sound playback in the Barber Joe minigame of Rodney's Funscreen.

Fixes mouse cursor relative position in the Barber Joe minigame of
Rodney's Funscreen.

Fixes crash in the shooting minigame in Gus Goes to the Kooky Carnival.

Prevents a ~1 frame gap with the incorrect palette.

The RLE format does support specifying what the foreground colour is,
but by default it uses the one in the RichTextCastMember metadata. So
you need to hold off on generating the bitmap until you know what that
is. We now use the PixelFormat to give us the correct colour
values instead of doing bad maths.