Pyscada

- fixed re-login after logout (22)
- added LINK_TARGET option to change the default behaviour of links in view overview (23)
- Catching exceptions if DB close while pyscada is running

- fixed zombi process problem
- fixed migrations with python3
- changed datetime_now to now from django timezone

- update to flot 2.1.6
- fixed process flow diagram value not displayed
- moved x y zoom selection in HMI to each Chart
- add option of redirecting to a custom login page
- add framer option for modbus communication
- add data courser in chart
- add XYChart
- add new form widget in HMI
- add new drop down control element in HMI
- fixed WidgetContent not being deleted
- moved signal related methods to dedicated signals.py
- added pyserial to dependency list
- improved hmi <--> db communication to avoid data loss on slow connections

- updated docs, switching from python 2.7 to python 3
- added redirect to https to the nginx sample config
- fixed server error for BackgroundProcess View in Admin with python3
- fixed HDF5 export for python 3
- fixed ProcessFlowDiagram in HMI
- added support for multiple SlidingSidePanels on one Side
- added date_saved field to the RecordedData Model, renamed the RecordedData model without the field to RecordedDataOld,
migration 48 will copy some data to the new model, the rest can be copied by using the move_data.py script

- fixed issue 13, Mismatch between event limit elif cases and the displayed limit types.
- merged pull request 12, changing from source_format to target_format to match preceding setting of '2H' value

- changed widget model to support content from plugins
- changed visable to visible in pyscada.hmi.models.Chart, SlidingPanelMenu, Widget
- some changes for python 3 compatibility in pyscada.export