Allow classoptions in tf_article() (#434)

* Allow classoptions such as `letterpaper`
* Using a for loop to support multiple classoptions

Co-authored-by: christophe dervieux <[email protected]>

Author: statzhero

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: rticles
 Type: Package
 Title: Article Formats for R Markdown
-Version: 0.20.3
+Version: 0.20.4
 Authors@R: c(
   person("JJ", "Allaire", role = "aut", email = "[email protected]"),
   person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),

NEWS.md

@@ -1,7 +1,11 @@
 # rticles 0.21
 
+- Template for `tf_article()` gains a `classoption` variable (thanks, @statzhero, #434).
+
 - Add the fenced div with id `#refs` in `frontiers_article()` skeleton to place the reference section in the correct expected place (thanks, @graysonwhite, #423).
+
 - `bioinformatics_article()` has no more trailing comma after last author (thanks, @stephenturner, #413).
+
 - `bioinformatics_article()` now separates `manuscript_type` (e.g., Applications note, Original article) and `subject_section` (e.g. Genome analysis, Phylogenetics) in template and skeleton (thanks, @stephenturner, #415)
 
 # rticles 0.20

inst/rmarkdown/templates/tf/resources/template.tex

@@ -1,7 +1,7 @@
 % interactcadsample.tex
 % v1.03 - April 2017
 
-\documentclass[]{interact}
+\documentclass[$for(classoption)$$classoption$$sep$,$endfor$]{interact}
 
 \usepackage{epstopdf}% To incorporate .eps illustrations using PDFLaTeX, etc.
 \usepackage{subfigure}% Support for small, `sub' figures and tables