Add shader compiler (nzslc) and use it

tools/nzslc.lua

@@ -0,0 +1,18 @@
+add_requires("cxxopts")
+
+target("NazaraShaderCompiler")
+    set_group("Tools")
+    set_kind("binary")
+	set_basename("nzslc")
+
+    add_deps("NazaraShader")
+    add_packages("cxxopts", "fmt")
+
+    if has_config("unitybuild") then
+        add_rules("c++.unity_build")
+    end
+
+    add_includedirs("../src")
+    add_headerfiles("../src/ShaderCompiler/**.hpp", "../src/ShaderCompiler/**.inl")
+    add_files("../src/ShaderCompiler/**.cpp")
+    set_policy("build.across_targets_in_parallel", false)