eeschema now supports arbitrary colors for all object types, and
pcbnew does in GAL canvas. When switching from GAL to legacy canvas,
pcbnew will convert colors to the nearest legacy color.
Move items rework: enhancements: for some items (sheets, components, bus entries) the mouse cursor is no more wrapped to the anchor. For large symbols, this is better: they are more easy to place.
There is also a change when starting a move item command: the full screen is redraw, and therefore there is no artifact due to the XOR draw mode.
Some other minor coverity fixes (uninitialized members).
* move not shared files (sch_item_struct.*, sch_base_frame.h) to eeschema;
* move wxEeschemaStruct.h to eeschema and rename it schframe.h to be consistent with the other corresponding file name schframe.cpp;
* remove few not needed #include