close #42: enable AppVeyor just to test the TeX Live installer

Author: yihui

.Rbuildignore

@@ -2,3 +2,4 @@
 ^\.Rproj\.user$
 ^tools$
 ^\.travis\.yml$
+^appveyor\.yml$

README.md

@@ -1,6 +1,7 @@
 # TinyTeX
 
 [![Build Status](https://travis-ci.org/yihui/tinytex.svg)](https://travis-ci.org/yihui/tinytex)
+[![AppVeyor build status](https://ci.appveyor.com/api/projects/status/github/yihui/tinytex.svg)](https://ci.appveyor.com/project/yihui/tinytex)
 [![Downloads from the RStudio CRAN mirror](https://cranlogs.r-pkg.org/badges/tinytex)](https://cran.rstudio.org/package=tinytex)
 
 The installation and maintenance of LaTeX have bothered me for several years. Yes, there are MiKTeX, MacTeX, and TeX Live, but the common problems are:

appveyor.yml

@@ -0,0 +1,10 @@
+init:
+  ps: Invoke-WebRequest https://github.com/yihui/tinytex/raw/master/tools/install-windows.bat -OutFile install-windows.bat
+
+build_script:
+  - install-windows.bat
+
+test_script:
+  - tlmgr --version
+  - pdflatex --version
+  - xelatex --version