unitizer_ls: An `ls` Like Function
Description
Much like `ls`, except that it is designed to crawl up the `.new` and
`.ref` environments and display all the objects.
Usage
unitizer_ls(
  name,
  pos = -1L,
  envir = parent.frame(),
  all.names = FALSE,
  pattern
)
Value
list of object names, or a list with environments containing the
  objects
Details
This is used in `browseUnitizer,unitizer-unitizerBrowse-method`,
and is re-assigned to `ls` for use in the `unitizer` prompt
environment.