-fixed code do cross compiling to android
-fixed build with GCC (workaround)
-added little benchmark
-several small fixes
-updated meson build (demos building, working with GCC, LDC and DMD)
-added some meson options
-added ImGUI bind for OpenGL3
-empty components now take no memory, so flag components is now far better
-added test for critical bug
-fixed critical bug with adding/removing entities form inside events
-fixed small bug with TestRunner
-improve basic tests
-fixed betterC compilation on DMD
-remove EntityID form Event structure
-added "return" attribute to some functions
-moved some code from Tempalte side to actual implementation
-fixed bug with EntityTemplate copying
-commented out some possibliy unused code
-use code formatter
-fixed issue with adding/removing entities inside events handling
-fixed EntityMeta.getComponent() (added check if component_id is valid)
-added function hasComponent to entity to check if component exists
