rticles 0.6

• Added the template for the SAGE Journals (thanks, @oguzhanogreden, #181).

• Added the template for Biometrics (thanks, @daltonhance, #170).

• Added the template for Copernicus Publications journals (thanks, @nuest, #172).

• Supports syntax highlighting in the ieee_article() and acm_article() formats (thanks, @rainer-rq-koelle, #182).

• Disabled syntax highlighting for rjournal_article() (thanks, @eddelbuettel, #185).