* Schematic editor cancel current tool command now use a single command
ID that is used everywhere the event is generated.
* Moved cancel current tool code from Process_Special_Functions to a
separate event handler.
* Add idle check method to block select object.
* Add block active check to base screen object.
* Changed managed cursor callback definition to include the current
cursor drawing position.
* Modified all managed cursor callbacks to match new definition.
* Added snap to grid option to base drawing frame object.
* Changed add no connect managed cursor callback to use new position
parameter instead of the stored one.
* Lots of coding policy fixes.
* Move schematic wire and bus break code into schematic screen object.
* Move schematic test for dangling ends into schematic screen object.
* Remove left over debugging output in schematic screen object.
* Remove unused file eeschema/cleanup.cpp.
* Fix bug in schematic line object hit test algorithm.
* Fix a string concatenation compile error added in r2752.
* Rename class WinEDA_BasicFrame to EDA_BASE_FRAME.
* Rename class WinEDA_DrawFrame to EDA_DRAW_FRAME.
* Rename class WinEDA_DrawPanel to EDA_DRAW_PANEL.
* Move schematic select block from global variable to SCH_EDIT_FRAME.
* Remove redundant schematic drawing code for eeredraw.cpp.
* Move block select code into SCH_SCREEN object.
* Simpilify block item select code.
* Fix bug in SCH_LINE selection state test.
* Add test to schematic objects for connectability.
* Make copy block items function a private method in SCH_EDIT_FRAME.