Added membed tutorial

.gitignore

 target
+*~
+
+embed/node_modules

embed/Cargo.lock

+[root]
+name = "embed"
+version = "0.1.0"
+

embed/Cargo.toml

+[package]
+name = "embed"
+version = "0.1.0"
+authors = ["Anders Nilsson <anders.nilsson@control.lth.se>"]
+
+[lib]
+name ="embed"
+crate-type = ["dylib"]

embed/embed.js

+var ffi = require('ffi');
+
+var lib = ffi.Library('../target/release/libembed', {
+  'process': ['void', []]
+});
+
+lib.process();
+
+console.log("done!");

embed/embed.py

+from ctypes import cdll
+
+lib = cdll.LoadLibrary("../target/release/libembed.so")
+
+lib.process()
+
+print("done!")

embed/embed.rb

+require 'ffi'
+
+module Hello
+  extend FFI::Library
+  ffi_lib '../target/release/libembed.so'
+  attach_function :process, [], :void
+end
+
+Hello.process
+
+puts 'done!'

embed/src/lib.rs

+use std::thread;
+
+#[no_mangle]
+pub extern fn process() {
+    let handles: Vec<_> = (0..10).map(|_| {
+        thread::spawn(|| {
+            let mut x = 0;
+            for _ in (0..15_000_000) {
+                x += 1
+            }
+            x
+        })
+    }).collect();
+
+    for h in handles {
+        println!("Thread finished with count={}",h.join().map_err(|_|"Could not join a thread!").unwrap());
+    }
+    println!("done!");
+}

embed/toy.rb

+threads = []
+
+10.times do
+  threads << Thread.new do
+    count = 0
+
+    15_000_000.times do
+      count += 1
+    end
+
+    count
+  end
+end
+
+threads.each do |t|
+  puts "Thread finished with count=#{t.value}"
+end
+puts "done!"