This is used to provide menu entries that allows cancellation of
interactive drawing and routing tools without needing the keyboard.
It is provided in the drawing tools and the router tool.
The cancel event doesn't have any new functionality (e.g. track rip-up
for the PNS router - lp:1448460), this just adds it to the menu, where
it behaves the same as an Escape keypress.
Some grid/zoom tools are left in PCBNEW_CONTROL because they currently
depend on Pcbnew-specific class members. Once refactoring is done to
make it possible to use all zoom and grid controls outside of pcbnew,
these last tools can be moved to common to match their ACTIONs.
New virtual class ACTIONS is added as a member to EDA_DRAW_FRAME so
that the TOOL_DISPATCHER can have access to the appropriate derived
version of TranslateLegacyId()
Jon Evans
John Beard