cosimameyer/overviewR: JOSS paper archival

This release entails all changes requested by reviewers at JOSS:

• Added overview table that puts overviewR in perspective with other R packages (in README)
• Make code visible how to generate modified toydata data sets (in README)
• Rename overview_print to overview_latex
• Deprecate separate file and path arguments in overview_latex and add file_path instead
• It also includes the paper and all accompanying material in paper/