Unique term

This module was written to solve node upload module's problem. The reason I did not create it as patch, that it can be usefull as a separeted module.

When node upload module create nodes from images it creates new terms for each node (depend on settings), so finally you have same term names on different urls.

This module implement hook_taxonomy_term_presave, and look for existing terms, if found use it instead of create a new one.