Release 5.2.0 (#197) * [chore] bump version * [docs] Fixing broken URLs - Removed Paul Tol URLs - updated WSJ twitter URL

Prepare for CRAN submission (#167) * Remove WSJ twitpic examples They are now inaccessible. * Update highcharts URL * Fix doc example error * Fix highcharts links and docs * Fix spelling * Increment version number to 4.3.0 * Bump version to past 5.1.0 There was some sort of problem in which local commits that were included in CRAN were not synced with Github and lost. * CRAN submission

Update cran-release 

Bump version Closes #78

update version 

Merge branch 'dev' 

rebuild docs 

update docs 

roxygenize 

fixing bug from last commit forgot to import stats