Added ita_roomacoustics_kurtosis that implements the descriptor proposed in...

Added ita_roomacoustics_kurtosis that implements the descriptor proposed in Jeong "Kurtosis of room impulse responses as a diffuseness measure for reverberation chambers" J. Acoust. Soc. Am. 139 (5), 2016.

applications/RoomAcoustics/AdditionalRoutines/ita_roomacoustics_kurtosis.m

+function varargout = ita_roomacoustics_kurtosis(varargin)
+%ITA_ROOMACOUSTICS_KURTOSIS - +++ Short Description here +++
+% This function calculates the kurtosis of room impulse responses as a
+% diffuseness measure as proposed by Jeong for reverberation chambers in
+% Cheol-Ho Jeong "Kurtosis of room impulse responses as a diffuseness
+% measure for reverberation chambers" J. Acoust. Soc. Am. 139 (5), May 2016
+%
+%  Syntax:
+%   varargout = ita_roomacoustics_kurtosis(audioObjIn, options)
+%
+%   Options (default):
+%           'freqRange'      [125*2^(-1/2) 4e3*2^(1/2)]  : preferred frequncy range
+%           'timeRange'      [10e-3 100e-3] : preferred time range
+%
+%  Example:
+%   audioObjOut = ita_roomacoustics_kurtosis(audioObjIn)
+%
+%  See also:
+%   ita_toolbox_gui, ita_read, ita_write, ita_generate
+%
+%   Reference page in Help browser
+%        <a href="matlab:doc ita_roomacoustics_kurtosis">doc ita_roomacoustics_kurtosis</a>
+
+% <ITA-Toolbox>
+% This file is part of the ITA-Toolbox. Some rights reserved.
+% You can find the license for this m-file in the license.txt file in the ITA-Toolbox folder.
+% </ITA-Toolbox>
+
+
+% Author: Ernesto Accolti -- Email: eac@akustik.rwth-aachen.de
+% Created:  08-Jan-2020
+
+
+%% Initialization and Input Parsing
+fr=[125*2^(-1/2) 4e3*2^(1/2)]; % default frequncy range
+tr=[10e-3 100e-3]; % default time range
+sArgs         = struct('pos1_data','itaAudio','freqRange',fr,'timeRange',tr);
+[input,sArgs] = ita_parse_arguments(sArgs,varargin);
+
+%% Main code
+
+% filter
+input=ita_filter_bandpass(input,'zerophase', true,'order',10,'upper', ...
+    sArgs.freqRange(2),'lower', sArgs.freqRange(1));
+
+% time shift 
+nShiftSamples = ita_start_IR(input);
+input=ita_time_shift(input,-nShiftSamples,'samples'); 
+% MAIN
+Nr=sArgs.timeRange*input.samplingRate;
+k = kurtosis(input.timeData((Nr(1):Nr(2)),:));
+
+
+%% Output
+varargout={k};
+
+%end function
+end
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