Fix typos and spelling.

include/osgShadow/MinimalShadowMap

@@ -90,7 +90,7 @@ class OSGSHADOW_EXPORT MinimalShadowMap : public StandardShadowMap
         // when scene objects are put on earth ellipsoid surface.
 
         // Other scenarios are also possible for example when models are
-        // built in XZY space which would require identity matrix with swapped colums
+        // built in XZY space which would require identity matrix with swapped columns
 
         osg::Matrix                        _modellingSpaceToWorld;
         float                              _maxFarPlane;

include/osgShadow/StandardShadowMap

@@ -61,7 +61,7 @@ class OSGSHADOW_EXPORT StandardShadowMap : public DebugShadowMap
         // Example: Imagine we want to swap base(0) and shadow(1) indices:
         // We have to do an extra step to make sure both do not end up as 1
         //
-        // // initialy change base to something else than 1
+        // // initially change base to something else than 1
         // setBaseTextureCoordIndex( 100 );
         // // now search and replace all gl_TexCord[1] to gl_TexCord[0]
         // setShadowTextureCoordIndex( 0 );