haploR: Query 'HaploReg', 'RegulomeDB'

#' @importFrom httr POST GET content 
#' @importFrom httr upload_file timeout user_agent
#' @importFrom httr config set_config
#' @importFrom XML htmlTreeParse htmlTreeParse xpathApply
#' @importFrom XML xmlValue xmlGetAttr readHTMLTable
#' @importFrom XML htmlParse xpathSApply
#' @importFrom tibble as_tibble
#' @importFrom RUnit checkEqualsNumeric checkTrue
#' @importFrom plyr ldply
#' @importFrom utils read.csv
#' @importFrom stats runif setNames
#' @importFrom RCurl url.exists getURL
#' @importFrom DT datatable formatStyle styleInterval %>% 
#' @importFrom RJSONIO fromJSON
#' @importFrom methods is
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