Hopefully the AI is better (lol)

- Changed the enemy AI to use a Line of Sight system, where, within a certain radius from the player, if the Mob's LoS to the player gets broken, it searches an invisible grid of points (each of which also have a LoS to the player or not) for the closest point that both has LoS to the mob itself and the player and then it goes to that point, before re-checking LoS to the player and either moves towards the player or repeats the process. Shoutout to Challacade's "Creating SMART enemies from scratch! | Devlog" Youtube video for the idea. It took a while to implement properly but I think it works fairly well. Still some issues, but at least the enemies aren't just trying to run STRAIGHT at the player the entire time.

- Added back in some upper level blocks to see how the AI changes work with them (beware that mobs can still hit you from below on this platforms)

- Added Level Requirement text in the store for each upgrade

- Added some cool fire sprites and lights I found, along with darkening the overall scene in general

- Made it so that hearts and mana orbs that are dropped by mobs do not disappear if you walk into them while at fully health/mana respectively. Along with this I slightly lowered the drop rate of those items since there should be more on the ground to pick up at any given time.

- Made it so that the tree's become slightly transparent if mobs or the player are behind them