* Rename all member variables and methods that reference the cross hair
code in draw panel object from cursor to cross hair to eliminate confusion
between the two concepts.
* Rename cursor capture call backs in draw panel object to improve code
readability.
* Create helper class for turning off the cross hair while drawing.
* Remove redundant block clear code.
* Remove redundant mouse capture call back reset code when end capture
call back is called.
* Remove unused function definitions in base draw frame object.
* Lots of minor coding policy and doxygen comment fixes.
* Fix rendering bug in GerbView caused by wxDC scaling change caused by
setting the wxDC clipping region.
* Eliminate the need to have optional background erasing as the change
above fixed that problem as well.
* Default cursor handling improvements.
* 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.
Rename EDA_Rect::Inside to EDA_Rect::Contains ( EDA_Rect::Inside( const EDA_Rect& aRect ) was very ambiguous )
Fix some Doxygen warnings and erroneous comments; Add comments.