Caves done + various fixes!

So after almost 2 months of further coding the cave system is completely done (*cough cough* except for the main events). Additionally a lot of bug fixes as well as the fact that now killing enemies through "non-conventional" methods (i.e. literally anything other than your normal attacks such as minions, damage over time effects or explosions) will now be registered by the game as you actually killing them. This will be specially important for the newly added class: The plague doctor - who can poison enemies and resummon their corpses as zombies.

In addition to the caves I have also completed the 2nd of 7 black towers (and the guarding boss that comes with it).  My next goal will be to complete the rest of the northern continent (which covers the last black tower as well as the 2 last icy areas).

Oh and I should also mention the 2 most important changes in regarding to difficulty/length of the game:

- Enemies' stats now scale over time - the difference is currently barely noticable (I will experiment with this a bit more to figure out a good ratio for this)

- The revival/respawn system: Now both players dying results in the end of your run rather than just respawning, and the time you are allowed to try to revive your partner before dying yourself is reduced the higher your level is. In exchange for that, the first 4 times anyone dies you get revived for free.