Dependencies and path-finding.

Hi everyone,

The last week-end, I spent a bit of time in changing Valyria's Tear dependencies.
Just like anything sensible, the dependency problem is something tedious one has to take care very softly.

To be honest, and since Allacrost already used SDL, I took the way of adding the SDLImage dependency that will take care from now on to load the image data.
Since the SDL Image library is made by specialists and tested by a lot of people, it will ease the pain of testing libpng direct calls for that case.

More importantly, I've also been working on the collision detection algorithm.
After a lot of pain and struggle with the existing system, I simply took the step to rewrite it from scratch, and it came out much more simply than I thought.
The previous algorithm was splitted into about four functions, each containing their own limitations and historical bugs, making it all a nightmare to debug.
The new implementation is much smaller and permit to fix most cases, uncluding pathfinding and sprites untangling, and permit also not to block the player or a NPC when it is walking diagonally against a wall, by making it fall back to the free straight direction in that case.

I guess a big final step forward as been made in this sensible area, as you can see, and the only blocker left to make a first complete episode so far (art excepted) is the rewrite of the shop mode :)

Stay tuned ;)