Fix make file to work.
Added empty main.c
Updated .gitignore for xcode project
Added xcode project.
Merge branch 'feature/xcode-project' into develop
Added another xcode file to .gitignore.
Added code for running tests.
Add test action.
Merge pull request #1 from gjb7/feature/testing

Unit testing
Fix Makefile for unit testing.
Fix main.c for running unit tests.
Add base entity code.
Implement basic test for entities.
Clean before doing stuff.
Simplified freeing an entity.
Simplify tests.
Merge pull request #2 from gjb7/feature/entity

Entity
Make compiling with glib work.
Add entity hierarchy.
Add test for entity hierarchy.