Added space behind the cave2 shroom to hint about its game mechanism.

Thanks to Gallaecio and shirish for pointing out.
Changed the attribute modification scale to make it more game-long suitable.

The attribute changes were very high or low alone, and with both the appliance
of equipment and battle effects, any monster/character could become either
a killer or almost harmless, even at high levels.
Fixed a dumb mistake in one of Harlequin skills.
Fixed a big gap in battle stats initialization.

I noticed that while fixing the modifiers. In fact, I forgot to apply the same
rule at battle start than when restarting a battle leading to erroneous values
obtained after removing an effect in certain cases.

It is now fixed.
Used the correct function to compute the idle state time when reviving.

No need to reinvent the wheel, eh. :)
Improved the world map data loading/saving and added location id save support.

Note that for this to fix the location in Mt Elbrus, you have to reach the first
Mt. Elbrus map and save afterwards.

Part of #230
Improved the music state reset when returning in map mode after another game mode.

This will hopefully fix certain cases when the map music would stop after a battle.

Thanks to BioHazardX for pointing out.