Fix R CMD checks and update README

vignettes/bar_charts.Rmd

@@ -1,57 +0,0 @@
----
-title: "Bar charts"
-output: rmarkdown::html_vignette
-vignette: >
-  %\VignetteIndexEntry{Bar charts}
-  %\VignetteEngine{knitr::rmarkdown}
-  %\VignetteEncoding{UTF-8}
----
-
-```{r, include = FALSE}
-knitr::opts_chunk$set(
-  collapse = TRUE,
-  comment = "#>"
-)
-```
-Let's start by importing some data and running some data wrangling:
-```{r data-import}
-library(rio)
-library(data.table)
-dat <- import("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/11_SevCatOneNumNestedOneObsPerGroup.csv", data.table = TRUE)
-setDT(dat)
-
-# in all character columns, tranform empty string to NA
-vars_chr <- colnames(dat)[sapply(dat, is.character)]
-dat[, (vars_chr) := lapply(.SD, function(x) fifelse(x == "", NA_character_, x)), .SDcols = vars_chr]
-
-# in value, if -1 replace with NA
-dat[, value := fifelse(value == -1, NA_real_, value)]
-
-# remove lines where value is NA (in place)
-dat <- dat[!is.na(value), ]
-
-# kepp only top 20 values and divide data to get million units
-df <- dat[
-  !is.na(value), ][
-  order(value, decreasing = TRUE), ][
-  1:20, ][
-  , value := value/1000000, ][
-  , key := ifelse(key == "Democratic Republic of the Congo", "DRC", key)]
-```
-
-Now, let's see the defaults for a horizontal bar diagram without any grouping and ordering values from highest to smallest:
-
-```{r hbar}
-library(visualizeR)
-
-hbar(
-  df,
-  x = "key",
-  y = "value",
-  facet = "region",
-  order = "y",
-  title = "Top 20 countries by population (in Million)"
-)
-```
-
-Moving on to a vertical bar chart, with country facets and groups