Turned actor stats into a container handling a base + a modifier.

This will permit to never touch the base value and simply apply modifiers
on it, just as it is done with the attack points.

For now, the active (from battle) modifiers are applied correctly.
The code applying the passive ones (still in the battle code) is in fact wrong
and should be moved to the globalactor class along with a good fix.
Yet, this will be for another commit.

Along the way, this was also done and/or needed to be done:
- Removed dead code
- Fixed the enemies using the strength value as vigor in battles.
- Ironed out the status effect lua function calls to prevent game crashes,
  seen mostly in the debug battle.
- Fixed bugs in the status effect Remove() functions and old enums used
  in the elixirs lua code.
Big status effect handling overhaul.

- Merged elemental effects into status effects completely.
I removed them from being applied within the equipment as
it was the wrong way of doing it.

- Added support for passive and active status effects in battles,
and when equipping/unequiping.
I thus removed the old status effect handling code from the battle mode.

- Simplified the status.lua file by removing duplicate scripting,
and added support for passive effect calls there and in the engine.

- Fixed the improper use of copy construction for global stats instead
of setting their base value.

- Added support for SP damage/stealing to finish an effect.

The status effect code is now much saner and extensible. :D
What's lacking now is some code to call updates for passive (equipment) effects
in battles and proper support of both passive and active effects in the map mode,
but at least the core mechanisms are in a good shape now.
Fixed two off-by-one errors pointed out by codergreen.

A big thanks to him for that! :)
Added ellipse shape support to the particle effects.

I used it to make the circles seen in the battle mode better looking.
Made the passive effects be updated in battles.

I also started moving some common logic back to the global status effect
class.

And I tried to clarify in the status.lua what is a battle function
and what is global one.

What's left is to create a passive status effect class for battles
as the use of full battle status effects is useless for passive effects.

And had the same functionalities for the map mode.

Yet, this is sufficient to close #141
Started to keep on the next maps.
Centered the character when saving its position.

Previously, the character would appear on the bottom-center of the save point circle, sometimes showing a glitch with the particle effects when loading a game.

You'll have to save again to appear to make your character appear centered at next loading.
Fixed passive status effects handling

The passive status effects handling wasn't working at commit time. This is now fixed.
Fixed displaying the battle actor stun icon when in command menu.
Merge pull request #187 from authenticate/upstream

Added a UI theme option to the boot options menu.
Reverting VS project warning settings and .gitignore changes. This is a fork side only commit.
Adding a submodule for the VS2012 dependencies.
Fixing all level 4 warnings and higher.  This is a fork side only commit.
Update README