Merge branch '2.1' into 2.2

# Conflicts:
#	gns3server/compute/docker/docker_vm.py
#	gns3server/controller/compute.py
#	gns3server/controller/gns3vm/__init__.py
#	gns3server/controller/link.py
#	gns3server/controller/project.py
#	gns3server/handlers/api/controller/project_handler.py
#	gns3server/handlers/api/controller/server_handler.py
#	gns3server/utils/asyncio/__init__.py
#	gns3server/utils/asyncio/telnet_server.py
#	gns3server/version.py
#	gns3server/web/web_server.py
#	tests/compute/qemu/test_qemu_vm.py

gns3server/utils/asyncio/__init__.py

@@ -160,32 +160,32 @@ def wait_for_named_pipe_creation(pipe_path, timeout=60):
             return
     raise asyncio.TimeoutError()
 
+#FIXME: Use the following wrapper when we drop Python 3.4 and use the async def syntax
+# def locking(f):
+#
+#     @wraps(f)
+#     async def wrapper(oself, *args, **kwargs):
+#         lock_name = "__" + f.__name__ + "_lock"
+#         if not hasattr(oself, lock_name):
+#             setattr(oself, lock_name, asyncio.Lock())
+#         async with getattr(oself, lock_name):
+#             return await f(oself, *args, **kwargs)
+#     return wrapper
 
-def locked_coroutine(f):
-    """
-    Method decorator that replace asyncio.coroutine that guarantee
-    that this specific method of this class instance will not be
-    executed twice at the same time
-    """
-    @asyncio.coroutine
-    def new_function(*args, **kwargs):
+def locking(f):
 
-        # In the instance of the class we will store
-        # a lock has an attribute.
-        lock_var_name = "__" + f.__name__ + "_lock"
-        if not hasattr(args[0], lock_var_name):
-            setattr(args[0], lock_var_name, asyncio.Lock())
+    @functools.wraps(f)
+    def wrapper(oself, *args, **kwargs):
+        lock_name = "__" + f.__name__ + "_lock"
+        if not hasattr(oself, lock_name):
+            setattr(oself, lock_name, asyncio.Lock())
+        with (yield from getattr(oself, lock_name)):
+            return (yield from f(oself, *args, **kwargs))
+    return wrapper
 
-        with (yield from getattr(args[0], lock_var_name)):
-            return (yield from f(*args, **kwargs))
-
-    return new_function
-
-
-# It's conservative approach to supported versions, please remove it when we drop the support to Python < 3.4.4
-if hasattr(asyncio, 'ensure_future'):
-    # python>=3.4.4
+#FIXME: conservative approach to supported versions, please remove it when we drop the support to Python < 3.4.4
+try:
+    from asyncio import ensure_future
     asyncio_ensure_future = asyncio.ensure_future
-else:
-    # deprecated
-    asyncio_ensure_future = asyncio.async
+except ImportError:
+    asyncio_ensure_future = getattr(asyncio, 'async')