PickPalette: fix call to `SetCellBackgroundColour`

How did this ever work? The signature was wrong according to the docs.
The last element should be the colour, not the first one.

render_map: select and deselect bitmap screen object each iteration from DC

The wx docs say that,

   ...before performing any other operations on the bitmap data, the
   bitmap must be selected out of the memory DC

which we immediately do right after when we fetch the raw pixel data.
So it therefore seems more semantically correct to deselect the bitmap
before running other non-DC operations, and re-selecting it again
before drawing a new room into it.

(Thanks Brad for the insight.)

render_map: whoops, gotta match the type of format specifier

render_maps: add a progress dialogue box

This was taking a long time for me. This only tracks phases 0 and 3
(the main backgrounds, AIUI, not sprites nor collision boxes) which
take a really long time to render on my machine.

Since all of my graphics processing slows down during render, I assume
wx is using up GPU. Guess my Intel GPU isn't powerful enough to render
this quickly?

render_map: move wxMemoryDC creation inside the loop

The previous version re-used the same wxMemoryDC object for all rooms,
which flooded the console with failed assertions like so:

(lizard_tool:25111): Gdk-CRITICAL **: 03:49:13.885: IA__gdk_draw_rectangle: assertion 'GDK_IS_DRAWABLE (drawable)' failed

The map then rendered using the first room data for all rooms.

From my understanding of the docs, you can't or shouldn't reuse
wxMemoryDC like this:

https://docs.wxwidgets.org/trunk/classwx_memory_d_c.html

It needs to be destroyed or reassigned after each usage. So the
simplest thing is to move it into loop so we just get a fresh drawing
board each iteration.

Data: fix incorrect condition in rename_item

Looks like this typo resulted in renaming anything causing the whole
sprite cache to be rebuilt. Rather minor problem.

Item: give trivial virtual dtors to all subclasses

I'm pretty sure this is safe, since there were no explicit dtors
anywhere before this. This is here to silence another compiler warning.

linting: fix some compiler warnings

* Init order in ctor-init lists
* Unneeded signed/unsigned comparisons
* Remove unused variables

.hgignore: update with build artifacts

makefile.tool: dumb new little makefile to build the tool, for me, in loonix

xcode8: add directory

Accidentally ignored by an overzealous .hgignore

main: use wxString instead of wxChar*

Maybe this worked in wx 2.8, but in 3.0 there's no conversion from
wxChar* to the wxString that the Package ctor expects.

panels: don't namespace inside the namespace

g++ doesn't like it when you try to redundantly specify the same
namespace when already in a namespace.

render_maps, render_sprites: use explicit enum type for image

Assigning the enum to an int raises a deprecation warning in wx 3.0
when passing in that into into the SaveFile function. Using the enum
type uses a non-deprecated SaveFile overload.

render_maps: use parens around C-style cast

I guess other compilers can parse this without parens, but g++ can't.

wx: add missing includes

I don't know if somehow these were all included by other files in wx
2.8, but in 3.0 these extra includes seem to be required.

is_background: match forward declaration to definition

The definition of this function is static, so it also needs the static
qualifier in its forward declaration.

assign_coins_and_flags: fix coordinate typo

g++ caught this because it made no sense to assign an, int, a float,
and an int to four ints.

openFileDialog: rename overwrite flag

It appears wx 3.0 has changed the name of this flag

init: check in source tarball, minus assets