Add Cairo as required package
In reference to issue #5
diff --git a/.Rproj.user/441ADA46/sources/per/t/12A15D18 b/.Rproj.user/441ADA46/sources/per/t/12A15D18
new file mode 100644
index 0000000..40be70d
--- /dev/null
+++ b/.Rproj.user/441ADA46/sources/per/t/12A15D18
@@ -0,0 +1,22 @@
+{
+ "collab_server" : "",
+ "contents" : "",
+ "created" : 1546910268699.000,
+ "dirty" : false,
+ "encoding" : "UTF-8",
+ "folds" : "",
+ "hash" : "3374608670",
+ "id" : "12A15D18",
+ "lastKnownWriteTime" : 1546912355,
+ "last_content_update" : 1546912355541,
+ "path" : "~/Documents/GitHub/posterdown/inst/rmarkdown/templates/posterdown_pdf/resources/template.tex",
+ "project_path" : "inst/rmarkdown/templates/posterdown_pdf/resources/template.tex",
+ "properties" : {
+ "cursorPosition" : "83,65",
+ "scrollLine" : "76"
+ },
+ "relative_order" : 2,
+ "source_on_save" : false,
+ "source_window" : "",
+ "type" : "tex"
+}
\ No newline at end of file