add posterdown_betterport

portrait template for better poster design has been added

- support for longer author list if needed, can specify various authors to be highlited in the begining of the list.

- better responsiveness to spacing when changinf poster size

-  may need to go back and ensure YAML options amon all templates are more standardized.
diff --git a/NAMESPACE b/NAMESPACE
index 1f7e92e..2f7ae9c 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,6 +1,7 @@
 # Generated by roxygen2: do not edit by hand
 
 export(posterdown_betterland)
+export(posterdown_betterport)
 export(posterdown_html)
 export(posterdown_latex)
 export(posterdown_pdf)