reset travis yml to original used by oshlack

.travis.yml

@@ -12,14 +12,14 @@ dist: xenial
 
 addons:
   apt:
-    update: true
-    sources:
-      - sourceline: 'ppa:opencpu/imagemagick'
+#    update: true
+#    sources:
+#      - sourceline: 'ppa:opencpu/imagemagick'
     packages:
       - libgsl-dev # dependency for gsl>copula>zinbwave
-      - libmagick++-dev # dependency for magick
+#      - libmagick++-dev # dependency for magick
 
-install: skip
+#install: skip
 #install:
 #  - R -e 'install.packages("knitr")'
 #  - R -e 'install.packages("devtools")'
@@ -27,7 +27,7 @@ install: skip
 
 after_success:
   - Rscript -e 'covr::codecov()'
-r_check_args: "--no-vignettes"
+#r_check_args: "--no-vignettes"
 notifications:
   email:
     recipients: