Fixed bug introduced by the PEP8 corrections
SkillSet class implemented

A container that collects skill definitions from other classes
and contains a current skill level. Each Entity has an effective skill
set. In case of Player, there is another skill set that is the result of
leveling skills, while the effective skill set is the skill combining
skills/weapons/armors/rings/status etc.
Standard fightsystem for magic and weapons

A set of functions called for standard weapons and magic, that
calculate the damage based on the attacker and defender skills.
The formulas are loosely based on the FF8 system.
Basic NPC implementation

Including changes to the skill/fight system, the update and render loop
and the basic Entity implementation. We now have walking and potentialy
killing/defeatable NPCs! But for some reason they won't die, probably
the player is a wimp. Or his attack action is incorrect. But, personaly,
I guess it is the former case.