ignore convention

[fdefalco]

An ongoing issue in our data operations pipeline occurs when we have data that enters our beta environment and our index which we do not want to move to our production environment. When this occurs we either have to manually edit the index file or move the entire release folder out of the directory before rerunning the indexer and moving the new index file.

We would like to introduce a convention by which the existence of an .aresIndexIgnore file in a data source folder or a data source release folder will instruct the indexer to ignore those folders when generating an index. Additional helper functions to describe what would be ignored or included would also be helpful.