Bug in dispersion plot where if word no.  1 was displayed
* `qdap_df` and `%&%` added to mimic some of the functionality of `dplyr`'s
  `tbl_df` and `%&gt;%` in a more specific, less flexible, `qdap` oriented way.

* `Text` added to view and change the `text.var` attribute of a `data.frame of
  the class `qdap_df`.
added to documentation
updated static docs