Fix typos and spelling.

include/osgWidget/Lua

@@ -23,7 +23,7 @@ namespace osgWidget {
 // Externally defined; does this work in Windows?
 struct LuaEngineData;
 
-// The actual Engine itself. Every attempt is made to export the implemenation into the
+// The actual Engine itself. Every attempt is made to export the implementation into the
 // source file, rather than having it here.
 class OSGWIDGET_EXPORT LuaEngine: public ScriptEngine
 {

include/osgWidget/Window

@@ -638,7 +638,7 @@ class OSGWIDGET_EXPORT Window:
         // This method is passed the additional values by which width and height should be
         // modified as calculed by the parent method, Window::resize. Keep in mind that these
         // values can be negative (indicating a potential "shrink" request) or positive (which
-        // would indicate a "grow" reqeust).
+        // would indicate a "grow" request).
         virtual void _resizeImplementation(point_type, point_type) = 0;
 
         // These are made into implementation functions since getting the width or height