add META to Readme.txt

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-i File             : Input audio File (WAV, raw PCM or scene description file)

-if Format          : Audio Format of input file (e.g. 5_1 or HOA3 or META, use -l for a list)

					  META is related to the Scene description file, see scripts/testv/renderer_config_format_readme.txt

-im Files           : Metadata files for ISM/MASA/OMASA/OSBA/BINAURAL_SPLIT_PCM (one file per object). 

                      For OMASA input, ISM files must be specified first.

-o File             : Output audio File

                                            left or l or 90->left, right or r or -90->right, center or c or 0 ->middle

-exof File          : External orientation trajectory File for simulation of external orientations

-dpid ID            : Directivity pattern ID(s) (space-separated list of up to 4 numbers can be 

                      specified) for binaural output configuration

                      specified) for binaural outputs

-aeid ID | File     : Acoustic environment ID (number > 0)

                      alternatively, it can be a text file where each line contains "ID duration" for BINAURAL_ROOM_REVERB output configuration.

                      alternatively, it can be a text file where each line contains "ID duration" for BINAURAL_ROOM_REVERB output.

-lp Position        : Output LFE position. Comma-delimited triplet of [gain, azimuth, elevation] where gain is linear 

                      (like --gain, -g) and azimuth, elevation are in degrees.

                                            If specified, overrides the default behavior which attempts to map input to output LFE channel(s)