waf: ardupilotwaf: use name without board extention

If the attribute name is passed, then it is the one used to process the option
--target[s] of waf build. The board name should be used only in configuration
time. The build targets should be board/platform agnostic.

Now, instead of using `waf --target ArduCopter.sitl`, we use `waf --target
ArduCopter` and the binary continues named as "ArduCopter.sitl".

README_waf.txt

@@ -25,8 +25,8 @@ calling just 'waf' is enough
 It's possible to build for just a vehicle or an example by specifying it as the
 target:
 
-    # From the top directory, note the board name used in the target
-    waf --target ArduCopter.linux
+    # From the top directory
+    waf --target ArduCopter
 
     # List all the targets available
     waf list

Tools/ardupilotwaf/ardupilotwaf.py

@@ -90,6 +90,7 @@ def program(bld, **kw):
     target = bld.bldnode.make_node(name + '.' + bld.env.BOARD)
     bld.program(
         target=target,
+        name=name,
         **kw
     )