-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
-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
*updated build scripts
*removed tls variables from code (needed to support WebAssembly)
*some mmutils tweaks
*some fixes
*pthread TLS thread ID implementation
-added Atomic file (reimplementation of atomics templates for emscripten)
-added emscripten support to ecs.std