Returns an object of class 'mefa', with non-nested segments. This function is internally used by the melt.mefa function.
References
S\'olymos P. (2008) mefa: an R package for handling and reporting count data. Community Ecology9, 125--127.
S\'olymos P. (2009) Processing ecological data in R with the mefa package. Journal of Statistical Software29(8), 1--28. http://www.jstatsoft.org/v29/i08/