[i18n] Initial i18n support.

- Add initial GetText .MO parser
- Add translation struct and helpers
- Pluralized lookup

 TODO:
- Support for more translation catalog file formats.

core/i18n/example/i18n_example.odin

@@ -0,0 +1,64 @@
+package i18n_example
+
+import "core:mem"
+import "core:fmt"
+import "core:i18n"
+
+LOC :: i18n.get
+
+_main :: proc() {
+	using fmt
+
+	err: i18n.Error
+
+	/*
+		Parse MO file and set it as the active translation so we can omit `get`'s "catalog" parameter.
+	*/
+	i18n.ACTIVE, err = i18n.parse_mo(#load("nl_NL.mo"))
+	defer i18n.destroy()
+
+	if err != .None { return }
+
+	/*
+		These are in the .MO catalog.
+	*/
+	println("-----")
+	println(LOC(""))
+	println("-----")
+	println(LOC("There are 69,105 leaves here."))
+	println("-----")
+	println(LOC("Hellope, World!"))
+
+	/*
+		For ease of use, pluralized lookup can use both singular and plural form as key for the same translation.
+	*/
+	println("-----")
+	printf(LOC("There is %d leaf.\n", 1), 1)
+	printf(LOC("There is %d leaf.\n", 42), 42)
+
+	printf(LOC("There are %d leaves.\n", 1), 1)
+	printf(LOC("There are %d leaves.\n", 42), 42)
+
+	/*
+		This isn't.
+	*/
+	println("-----")
+	println(LOC("Come visit us on Discord!"))
+}
+
+main :: proc() {
+	using fmt
+
+	track: mem.Tracking_Allocator
+	mem.tracking_allocator_init(&track, context.allocator)
+	context.allocator = mem.tracking_allocator(&track)
+
+	_main()
+
+	if len(track.allocation_map) > 0 {
+		println()
+		for _, v in track.allocation_map {
+			printf("%v Leaked %v bytes.\n", v.location, v.size)
+		}
+	}
+}