Fix units in formation blocking construction and not moving out of the way (see #779).

Make non-movement-blocking buildings (e.g. farms) not require units to
move out of the way.

This was SVN commit r9510.

source/simulation2/components/CCmpObstruction.cpp

@@ -289,6 +289,11 @@ public:
 		}
 	}
 
+	virtual bool GetBlockMovementFlag()
+	{
+		return (m_TemplateFlags & ICmpObstructionManager::FLAG_BLOCK_MOVEMENT) != 0;
+	}
+
 	virtual ICmpObstructionManager::tag_t GetObstruction()
 	{
 		return m_Tag;

source/simulation2/components/ICmpObstruction.cpp

@@ -27,5 +27,6 @@ DEFINE_INTERFACE_METHOD_0("CheckFoundationCollisions", bool, ICmpObstruction, Ch
 DEFINE_INTERFACE_METHOD_0("GetConstructionCollisions", std::vector<entity_id_t>, ICmpObstruction, GetConstructionCollisions)
 DEFINE_INTERFACE_METHOD_1("SetActive", void, ICmpObstruction, SetActive, bool)
 DEFINE_INTERFACE_METHOD_1("SetDisableBlockMovementPathfinding", void, ICmpObstruction, SetDisableBlockMovementPathfinding, bool)
+DEFINE_INTERFACE_METHOD_0("GetBlockMovementFlag", bool, ICmpObstruction, GetBlockMovementFlag)
 DEFINE_INTERFACE_METHOD_1("SetControlGroup", void, ICmpObstruction, SetControlGroup, entity_id_t)
 END_INTERFACE_WRAPPER(Obstruction)

source/simulation2/components/ICmpObstruction.h

@@ -56,6 +56,8 @@ public:
 
 	virtual void SetDisableBlockMovementPathfinding(bool disabled) = 0;
 
+	virtual bool GetBlockMovementFlag() = 0;
+
 	/**
 	 * Change the control group that the entity belongs to.
 	 * Control groups are used to let units ignore collisions with other units from