v1.3.14 Reduced compute time for in-doc examples

phyloseq 1.3.14
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- Shortened/replaced examples in the longest-running doc examples.
  This substantially reduces the time it takes to run package checks.

- Focused on worst offenders

- Created a new online tutorial for `subset_ord_plot`.
  Linked to it from `plot_ordination`

- `plot_taxa_bar` moved to deprecated function file where it belongs,
   and examples completely removed from doc.