-removed some unnecessary variables
-started C-API implemantation:
* added C-API option to Meson (build included to main library)
* refactored some code (moved some code form templates to final code, removed delegates from system)
* moved templates outside EntityManager to make it possible to use in different functions
-moved system destroy functionality to System structure "destroy()" function
-now arrays are properly destroyed (with destructor calling (__xdtor))
-fixed bug which makes BlockAllocator crashing after freeing it's memory
-fixed many smaller memory leaks