Polyline.h: remove useless class CRect. Use the more powerful EDA_RECT instead. Clean and remove duplicate code.
Fix python scripting issue (EDA_RECT not mapped)
Fix wxWidgets debug assertion for wxTextCtrl::IsSingleLine() in GTK.

* Fix assertions in Eeschema when editing net labels, electronic rules check,
  and plotting.
* Fix assertion when opening PCB calculator.
* Fix assertions in Pcbnew when changing footprints in footprint properties
  dialog and adding or editing text.
Improve MsgPanelInfo for line segments in the module editor
Factor out some common code in hotkeys_module_editor.cpp
Add EDGE_MODULE::RotateAboutOwnCenter() function
Make a start on exact moving
Add hotkey for move exactly
Extend move exactly to other types

Also add specific drawsegment centre-finding and rotation code.
Integrate block move exact and footpritn move exact
Fix whitespace
Duplicate hotkey - only works for pads
Duplicate for pads, text and edges, still need to do block