order.dendrogram<- function added.
intersect_trees function added
Updated doc -

Re-formatting (more will be needed), and added a package main doc.
labels.hclust - added the 'order' parameter
New: demo, vignettes (knitr), tests (testthat) -

all will need to be updated...
Fixes for CMD CHECK

1)
Change labels-set.Rd to labels-assign.Rd
And
order.denderogram-set.Rd to order.denderogram-assign.Rd
Added tests for labels assignment
vignettes - first part of the introduction written (it is a very rough draft, but readable).
tests - changed names, and added quick way for checking the code while developing the package.
"labels.hclust" and "labels.hclust<-" - now both use order=TRUE as default. this makes them consistent with labels.dendrogram. Proper tests have been implemented.
vingettes - labels assignment for vectors.