Adding options -s (settings) and -m (mappings)

These options were added because once mappings were created (and data was indexed), they cannot be changed in ElasticSearch. So it is necessary to create a new index, with the desired new mappings and then copy the data from the old index to the new one. This is where es-reindex comes in, but the previous code was forcing the copying of mappings. Now, by default es-reindex won't copy settings and mappings, only when -s and -m options are provided.