Update screenshot and QZV (#198)

* Update screenshot and QZV

* Update README and Makefile re: Emperor integration

* Add emp+emp screenshot to readme c/o @ElDeveloper

Makefile

@@ -48,3 +48,10 @@ docs:
 		--m-sample-metadata-file docs/moving-pictures/sample_metadata.tsv \
 		--m-feature-metadata-file docs/moving-pictures/taxonomy.qza \
 		--o-visualization docs/moving-pictures/empress-tree.qzv
+	qiime empress plot \
+		--i-tree docs/moving-pictures/rooted-tree.qza \
+		--i-feature-table docs/moving-pictures/table.qza \
+		--i-pcoa docs/moving-pictures/unweighted_unifrac_pcoa_results.qza \
+		--m-sample-metadata-file docs/moving-pictures/sample_metadata.tsv \
+		--m-feature-metadata-file docs/moving-pictures/taxonomy.qza \
+		--o-visualization docs/moving-pictures/empress-tree-tandem.qzv

README.md

@@ -31,6 +31,7 @@ download these individually from the URLs below (note some filenames
 may change due to the underlying hosting systems).
 
 - `rooted-tree.qza` [view](https://view.qiime2.org/?src=https%3A%2F%2Fdocs.qiime2.org%2F2019.10%2Fdata%2Ftutorials%2Fmoving-pictures%2Frooted-tree.qza) | [download](https://docs.qiime2.org/2019.10/data/tutorials/moving-pictures/rooted-tree.qza)
+- `unweighted_unifrac_pcoa_results.qza` [view](https://view.qiime2.org/?src=https%3A%2F%2Fdocs.qiime2.org%2F2019.10%2Fdata%2Ftutorials%2Fmoving-pictures%2Fcore-metrics-results%2Funweighted_unifrac_pcoa_results.qza) | [download](https://docs.qiime2.org/2019.10/data/tutorials/moving-pictures/core-metrics-results/unweighted_unifrac_pcoa_results.qza)
 - `table.qza` [view](https://view.qiime2.org/?src=https%3A%2F%2Fdocs.qiime2.org%2F2019.10%2Fdata%2Ftutorials%2Fmoving-pictures%2Ftable.qza) | [download](https://docs.qiime2.org/2019.10/data/tutorials/moving-pictures/table.qza)
 - `taxonomy.qza` [view](https://view.qiime2.org/?src=https%3A%2F%2Fdocs.qiime2.org%2F2019.10%2Fdata%2Ftutorials%2Fmoving-pictures%2Ftaxonomy.qza) | [download](https://docs.qiime2.org/2019.10/data/tutorials/moving-pictures/taxonomy.qza)
 - `sample_metadata.tsv` [download](https://data.qiime2.org/2019.10/tutorials/moving-pictures/sample_metadata.tsv)
@@ -39,6 +40,8 @@ From the base Empress directory, you can run `qiime empress plot` as shown
 below. Alternatively, if you've downloaded the files individually, you'll need
 to update the filepaths as needed.
 
+### Example 1: Using Empress to visualize a tree "standalone"
+
 ```bash
 qiime empress plot \
     --i-tree docs/moving-pictures/rooted-tree.qza \
@@ -48,20 +51,36 @@ qiime empress plot \
     --o-visualization docs/moving-pictures/empress-tree.qzv
 ```
 
-In this case, the resulting visualization will be saved to
+This generates a visualization of a phylogenetic tree at
 `docs/moving-pictures/empress-tree.qzv`.
 
+![Empress screenshot in q2view](https://raw.githubusercontent.com/biocore/empress/master/docs/moving-pictures/screenshot.png)
+
+### Example 2: Using Empress to visualize a tree in tandem with an ordination
+
+```bash
+qiime empress plot \
+    --i-tree docs/moving-pictures/rooted-tree.qza \
+    --i-pcoa docs/moving-pictures/unweighted_unifrac_pcoa_results.qza \
+    --i-feature-table docs/moving-pictures/table.qza \
+    --m-sample-metadata-file docs/moving-pictures/sample_metadata.tsv \
+    --m-feature-metadata-file docs/moving-pictures/taxonomy.qza \
+    --o-visualization docs/moving-pictures/empress-tree-tandem.qzv
+```
+
+This generates a visualization of a phylogenetic tree alongside a visualization
+of a PCoA plot (using Emperor) at `docs/moving-pictures/empress-tree-tandem.qzv`.
+
+![Empress and Emperor example GIF in q2view](https://raw.githubusercontent.com/biocore/empress/master/docs/moving-pictures/empress-emperor-example.gif)
+
 ##### Output Artifacts
 
 - `empress-tree.qzv` [view](https://view.qiime2.org/?src=https%3A%2F%2Fraw.githubusercontent.com%2Fbiocore%2Fempress%2Fmaster%2Fdocs%2Fmoving-pictures%2Fempress-tree.qzv) | [download](https://raw.githubusercontent.com/biocore/empress/master/docs/moving-pictures/empress-tree.qzv)
+- `empress-tree-tandem.qzv` [view](https://view.qiime2.org/?src=https%3A%2F%2Fraw.githubusercontent.com%2Fbiocore%2Fempress%2Fmaster%2Fdocs%2Fmoving-pictures%2Fempress-tree-tandem.qzv) | [download](https://raw.githubusercontent.com/biocore/empress/master/docs/moving-pictures/empress-tree-tandem.qzv)
 
 This QIIME 2 visualization can be viewed either using `qiime tools view` or by
 uploading it to [`view.qiime2.org`](https://view.qiime2.org).
 
-### Screenshot
-
-![Empress screenshot in q2view](https://raw.githubusercontent.com/biocore/empress/master/docs/moving-pictures/screenshot.png)
-
 ## Running Empress' Tests
 
 Please see the `tests/README.md` file for instructions on how to run Empress' tests.