Dtale

* [77](https://github.com/man-group/dtale/issues/77): removal of multiprocessed timeouts

* centralized global state

* allowing the usage of context variables within filters
* [64](https://github.com/man-group/dtale/issues/64): handling for loading duplicate data to dtale.show
* updated dtale.instances() to print urls rather than show all instances
* removal of Dash "Export to png" function
* passing data grid queries to chart page as default
* added sys.exit() to the thread that manages the reaper

* hotfix for KeyError loading metadata for columns with min/max information

* [63](https://github.com/man-group/dtale/issues/63): filtering columns with special characters in name
* added json_loader CLI options
* updated moving/locking of columns to be persisted to back-end as well as front-end
* added the ability to show/hide columns
* [61](https://github.com/man-group/dtale/issues/61): added column builder popup

* added the ability to move columns left or right as well as to the front
* added formatting capabilities for strings & dates
* persist formatting settings to popup on reopening
* bugfix for width-calculation on formatting change