* Add drag context menu entry for junctions that actually form a junction
with wires to EESchema.
* Add function to test for junctions to SCH_COLLECTOR class.
* Create annotate type and sort order enums to eliminate magic numbers
used in annotate code.
* Remove duplicate Doxygen comments from annotate.cpp and improve the
actual Doxygen comments in wxEeschemaStruct.h.
* Remove specialized edit reference, value, and foot print field methods
from SCH_FRAME object.
* Improve general field method to handle all field types as this was
essentially the same code used in the three methods removed.
* Updated the the hot key and context menu handlers to use the new field
edit method.
* Minor Doxygen comment warning fixes.
* Add item clarification context menu to EESchema when multiple unresolved
items are found at the current cross hair position.
* Add collector class SCH_COLLECTOR for supporting multiple item hit testing.
* Removed bit wise masked filtering from schematic item hit testing.
* Removed all old hit testing functions and methods scattered about the
EESchema source code.
* Move terminal point test function into SCH_SCREEN object.
* Fixed bug in terminal point test when terminating a bus to a label.
* Define the < operator for sorting schematic items.
* Add area calculation method to EDA_Rect item.
* Add method for returning an item's bitmap for menu display purposes.
* Add method for returning an item's menu text for menu display purposes.
* Changed EDA_ITEMS container from boost::ptr_vector to std::vector.
* Factor coordinate string conversion code from EDA_DRAW_FRAME to function
CoordinateToString().