Doublecheck if there is the possibility of a crash when you access a Feature that has its Layer deleted

[yeesian]

There is an immediate fix in #294. Opening this ticket to doublecheck the codebase for any other cases.

[evetion]

Not so much memory leak, but the possibility of a crash when you access a Feature that has its Layer deleted:

The returned feature becomes the responsibility of the caller to delete with OGR_F_Destroy(). It is critical that all features associated with an OGRLayer (more specifically an OGRFeatureDefn) be deleted before that layer/datasource is deleted.