Add `position` parameter to `navbarPage`
Update to Selectize 0.11.2 with computedstyle fix

Fixes #596
Bump selectize version in html dependencies
Update NEWS
fixes #605: send DT requests via POST instead of the default GET
Merge pull request #610 from yihui/bugfix/DT-POST

fixes #605: send DT requests via POST instead of the default GET
Merge pull request #597 from rstudio/selectize-0.11.0

Update to selectize 0.11.0
Merge remote-tracking branch 'origin/feature/bootstrap-navbar-pos'
escape HTML entities to avoid XSS attacks in DataTables

BTW, per recommendation of http://datatables.net/manual/server-side, the parameter `draw` is coerced to integer
per-column escaping
apply `escape` to column names as well
a news item for #627 [ci skip]
fix the issue reported by Tareef: dplyr tbl_df objects are also data frames, but the default non-standard evaluation df[, j] will fail in dataTablesJSON(), so we need to coerce such objects to data frames explicitly