Make use of live asset-reloading to update scripts while running

[NicoM1]

I think this is possible, but I'm not gonna attempt it for a while, because I'm not sure how I'll handle passing the relevant scripts to entities, due to many scripts being stored in the main xml file

[NicoM1]

Works for separate scripts now (ie scripts that aren't specified in xml) which I think its good enough because any script large enough to warrant editing at runtime should really be in its own file. Currently adding an (@)reload function, to allow changing variables after a reload (like what init does at startup)