Set fiber_properties::sched_algo_ every time through awakened().

Instead of setting a fiber_properties subclass's sched_algo_ back pointer once
at construction time, unconditionally set it every time that fiber becomes
READY (and is therefore passed to sched_algorithm::awakened()). This handles
the case in which that fiber migrates to a different thread with a different
sched_algorithm subclass instance.

Break out fiber_properties::notify() implementation to a separate .cpp
implementation file so it can bring in algorithm.hpp. We don't want
properties.hpp to depend on algorithm.hpp.

src/properties.cpp

@@ -0,0 +1,28 @@
+//          Copyright Oliver Kowalke 2013.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/assert.hpp>
+#include "boost/fiber/properties.hpp"
+#include "boost/fiber/algorithm.hpp"
+#include "boost/fiber/fiber_manager.hpp"
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace fibers {
+
+void fiber_properties::notify()
+{
+    BOOST_ASSERT(sched_algo_);
+    sched_algo_->property_change(fiber_, this);
+}
+
+}}                                  // boost::fiber
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif