FF: Indexhandler reindex performance is slow

[oyeaussie]

If we want to reindex the whole store, depending on the amount of indexes, the method reads through all the documents that many times along with rewriting the same file again and again. This is a bad method of reindexing the whole index.

[oyeaussie]

The fix applied is as follows:
We read all files only once and reindex them to an array. Once all indexes are generate, we dump the whole array to the index files. Performance has increased drastically. To index 20k documents with 7 indexes, it now take less than 5 seconds.