TINSEL: Fix subtle leak in coroutine code, some minor tweaks

* Fix a bug which caused coroutines invoked with nullContext to
  leak their state.
  Sadly, nullContext is underdocumented, yet very delicate and
  full of subtleties... ./
* Move nullContext decl from sched.cpp to coroutine.cpp
* Enhance a few doxygen comments

svn-id: r53934

1 files changed, 4 insertions, 0 deletions

diff --git a/engines/tinsel/coroutine.cpp b/engines/tinsel/coroutine.cpp
index 89d00d12ac..a1871f90b0 100644
--- a/engines/tinsel/coroutine.cpp
+++ b/engines/tinsel/coroutine.cpp
@@ -28,6 +28,10 @@
 
 namespace Tinsel {
 
+
+CoroContext nullContext = NULL;
+
+
 #if COROUTINE_DEBUG
 namespace {
 static int s_coroCount = 0;