Added support for post-effects drawing in the boot presentation.

And used it to add snow and a menu bar to make the menu more readable.

Conflicts:

	dat/config/boot.lua
Forgot to update two particle file doc
Random code cleanup.

Conflicts:

	src/modes/map/map.cpp
Fixed the map transition fade in and out by relying on the video manager
for the fade in timing.

What will be left is to pause the fade time when the game mode starting
the fade isn't active anymore.
Forgot to remove an empty file.
Removed the superfluous map context member.
Added debug flag for gcc debug builds.

You can type this to have a debug build, for instance:
cmake -DCMAKE_BUILD_TYPE=debug .
The big editor overhaul - part 1.

The editor got support for an arbitrary number of layer as for the internal code.

I also added a tree view where you can select the layer you want to edit.

I had to disable the map resizing, a part of the autotiling feature for now,
and the possibility to set a lyer's visibility,
so i could reach a convenient enough base to commit.

Note also that I intentionally removed the object layer support,
as it seemed incomplete, and not really necessary, at least for now.

Conflicts:

	src/editor/editor.cpp
Select the first layer at new map/load map time.
Made the new game fade out smooth.
Optimized the MapTile:DrawLayers() function a bit.

Since the std::map[] related calls were costy,
I simply made the function avoid making too much find calls.
Made the Drunes/XP counting not start automatically
from the  second battle.

This was coming from a static variable keeping its true value during
two battles sessions.
Made the number of total Drunes shown at battle win.

I also fine tuned the speed xp and drunes are counted
depending on their amount.
Worked around battle deaths and field revivals.

Now the characters party won't run if one of them is dead
at battles starts and ends.
A new Elixir item can revive a character which has 0 HP.

Made sure also that the potions can't revive a character,
and the MoonJuice Potion can't raise SP of a character in coma.
When the use has failed, the potion is currently still removed, yet.
Rationalized the way character recurrent graphics are loaded.

I made the portraits, stamina icon, and the battle animations
be loaded by the global script in a more flexible way.

This made the game complain only once about missing graphics,
but also simplified the code in many places.
Replaced the cursor blinking option in favour of a simple darken effect.

It's less 80s looking but less eyes hurting.
Made the map enemy sprites not blocking while spawning.

It seemed more logical game-wise and I can even guess
it was the previous behaviour.
Made the item not removed from inventory when they're used from the menu.

To acheive this, I made the fiekldUse functions return a boolean value,
fixed and memleak in the menu code, and factored a bit the lua potion
code.
Made the item given back to inventory whe its use failed.

To acheive this, I added return values to the battleUse lua functions.
Made possible to revive a character in a battle.

I added the code infrastructure to select dead characters
with special items, skills, and used that to add the revive state.