corcorana/restingIAF v1.0.2

Various updates and minor bug fixes, including:

• SGF parameters must now be specified (i.e. no default setting);
• 'psd' argument removed from call to pwelch in restingIAF;
• option to implement pwelch using an alternative taper to the default Hamming window;
• meanIAF reconfigured to cope with >2 sets of intraindividual recordings;
• plotAvSpec added to enable plotting of Q-weighted averaged channel spectra;
• tutorial updated to include example figures from plotAvSpec;
• simulation script separated into separate scripts for single/multi-component analyses;
• tutorial and simulation scripts updated in line with above modifications.