CRAN release

Update tests to support different CRAN system installations of texlive and potrace.

CRAN release

v1.4.6

Update tests/README.Rmd

CRAN release

• Fix non-tempdir() rendering
• Add texpreview_input print method for knitr_kable

CRAN release

• Convert tex_preview into S3 method
• Add print method for classes
• Add as.kable to convert tex lines into knitr_kable
• Update documentation for tex_preview
• Update and add vignettes

CRAN release

v1.3.2

tests: update covrpage and skip tlmgr test on nonunix sys