Add Pagination as an htmlwidget. Closes #20

[zeehio]

This pull requests allows to paginate an htmlTable object.

To do so, it offers a new function htmlTableWidget that takes a data frame and returns an htmlwidget with the paginated table, rendered using htmlTable.

library(htmlTable)
htmlTableWidget(iris)

The paginated table can be seen directly in the Viewer pane of RStudio and integrates well with Rmd files thanks to the dependency on htmlwidgets.

This pull request adds two additional functions htmlTableWidgetOutput and renderHtmlTableWidget to integrate the package with shiny.

This pull request closes #20