misc. typo fixes

mostly non-user-facing but some doxy.

include/osgParticle/Interpolator

@@ -39,7 +39,7 @@ namespace osgParticle
         virtual const char* className() const { return "Interpolator"; }
         virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const Interpolator* >(obj) != 0; }
 
-        /// Interpolate between floats. Must be overriden in descendant classes.
+        /// Interpolate between floats. Must be overridden in descendant classes.
         virtual float interpolate(float t, float y1, float y2) const = 0;
 
         /// Interpolate between 2-dimensional vectors. Default behavior is to interpolate each component separately.

include/osgParticle/Program

@@ -50,7 +50,7 @@ namespace osgParticle
         /// Implementation of <CODE>ParticleProcessor::process()</CODE>. Do not call this method by yourself.
         inline void process(double dt);
 
-        /// Execute the program on the particle system. Must be overriden in descendant classes.
+        /// Execute the program on the particle system. Must be overridden in descendant classes.
         virtual void execute(double dt) = 0;
 
     private:

include/osgParticle/Shooter

@@ -36,7 +36,7 @@ namespace osgParticle
         virtual const char* className() const { return "Shooter"; }
         virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const Shooter *>(obj) != 0; }
 
-        /**     Shoot a particle. Must be overriden by descendants.
+        /**     Shoot a particle. Must be overridden by descendants.
             This method should only set the velocity vector of particle <CODE>P</CODE>, leaving other
             attributes unchanged.
         */