Add a 'clone' parameter to /card route, use it in dashboard card links. Also fixes duplicate history entries when navigating to query builder

Fix object detail view so that columns with `:preview_display false` still show up

Improved webpack configuration, always build our own React but provide the correct flags to strip debugging info

fix up unit tests for query processor to account for adding `:preview_display` as part of the column metadata returned.

small css fix for pivot table styling.

Add documentation

add `:preview_display` in the column metadata returned from queries and avoid filtering out fields with :preview_display = false on `:rows` type queries.