EL 1.4

• Converted all legacy function documentation to roxygen2.
• EL.statistic() now returns an object of class "htest".
• Added FDEL.acf() for frequency-domain EL test of autocorrelation differences.
• Fixed axis label issues in EL.plot() and updated examples.
• Renamed d to Delta in EL.statistic() to align with theoretical notation; d is retained as a deprecated alias for backward compatibility.