alignment is applied on plots only (instead of on the chunk); \hfill{} can avoid the annoying large space caused by \end{center}
alignment is applied on plots only (instead of on the chunk); \hfill{} can avoid the annoying large space caused by \end{center}

fboehm/labnotebook,fboehm/cboettig_site,fboehm/labnotebook,fboehm/cboettig_site,fboehm/labnotebook,fboehm/labnotebook,fboehm/labnotebook,fboehm/labnotebook,antass/labnotebook3,fboehm/cboettig_site,fboehm/cboettig_site,fboehm/cboettig_site,antass/labnotebook3,antass/labnotebook3