Update anim.h

- Add missing whitespaces

include/assimp/anim.h

@@ -98,6 +98,7 @@ struct aiVectorKey {
     bool operator<(const aiVectorKey &rhs) const {
         return mTime < rhs.mTime;
     }
+    
     bool operator>(const aiVectorKey &rhs) const {
         return mTime > rhs.mTime;
     }
@@ -131,6 +132,7 @@ struct aiQuatKey {
     bool operator==(const aiQuatKey &rhs) const {
         return rhs.mValue == this->mValue;
     }
+    
     bool operator!=(const aiQuatKey &rhs) const {
         return rhs.mValue != this->mValue;
     }
@@ -139,6 +141,7 @@ struct aiQuatKey {
     bool operator<(const aiQuatKey &rhs) const {
         return mTime < rhs.mTime;
     }
+    
     bool operator>(const aiQuatKey &rhs) const {
         return mTime > rhs.mTime;
     }