Added Lua to lib folder and played around with EntityX before abandoning it because...

diff --cc Makefile
index cfd97d74cc16e020d9db16a17d4a4d1faa2a5ba5,46e61b73592a51a5aa9e6a9e228ab3aad9eaa940..107f936908332a6eca7172d677922407a1ddc5b7
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -21,12 -21,11 +21,12 @@@
  CC  = gcc
  CXX = g++
  
- LIBS = -lSDL2
 +LIBDIR = lib
+ LIBS = -lSDL2 -lpthread
  
  CXXFLAGS = -ggdb -std=c++17 \
 -      -Wall -Wextra -Werror -pedantic \
 -      -Isrc
 +      -Wall -Wextra -Werror -pedantic -Wno-unused\
 +      -Isrc -I$(LIBDIR)
  
  CXXSRCDIR = src
  CXXOUTDIR = out