-remove "SIMD" option from "compile_wasm.py" (new Emscripten hasn't that option)

-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

meson.build

@@ -5,11 +5,13 @@ betterC_opt = get_option('betterC')
 BuildDemos_opt = get_option('BuildDemos')
 BuildTests_opt = get_option('BuildTests')
 LTO_otp = get_option('LTO')
+C_API_opt = get_option('C-API')
 
 summary('betterC enabled', betterC_opt)
 summary('build demos', BuildDemos_opt)
 summary('build tests', BuildTests_opt)
 summary('LTO enabled', LTO_otp)
+summary('C-API enabled', C_API_opt)
 
 meson_minimum_version = '>=0.57.1'
 assert(meson.version().version_compare(meson_minimum_version), 'Newer verson of meson required, current version: @0@, required: @1@'.format(meson.version(), meson_minimum_version))
@@ -18,7 +20,14 @@ assert(meson.version().version_compare(meson_minimum_version), 'Newer verson of
 src = files()
 subdir('source')
 
-inc = include_directories('source/')
+inc = [include_directories('source/')]
+
+#C API files
+if C_API_opt
+	c_src = files()
+	subdir('c-api')
+	inc += include_directories('c-api/')
+endif
 
 # Arguments
 args = []