Update functions descriptions
Update functions descriptions

Update 'drop.clade.labels' description. Now it do not use 'extract.clade' or 'drop.tip' functions of 'ape' package. This can handle with or without singletons. Now it do not use 'nodedepth' function.

Update 'nodedepth' description an added an example. This functions is
kept as utility.

MarioJose/r-functions