Fetches a scholar's publications with get_publications and
calculates common citation metrics.
get_scholar_metrics(id, pagesize = 100, flush = FALSE)a data frame with h-index, g-index, i10-index, i50-index, i100-index, total citations, and publication count
a character string specifying the Google Scholar ID
an integer specifying the number of articles to fetch in one
batch. See get_publications.
should the publication cache be flushed?