Cursor position is saved as a field in order to avoid drifting of items while they are being dragged and rotated/flipped.

Resolved HOME hot key conflict between menu entry (Zoom Page) and event assigned to the hot key in the ACTION_MANAGER.
Conflicts:
	pcbnew/menubar_pcbframe.cpp

Added preference for selecting tracks/vias/graphics if there is a module present in the selection point.

- SEGVIA becomes VIA
- Drill size moved from TRACK to VIA
- Removed shape from TRACK, becomes ViaType in VIA
- GetTrace becomes GetTrack, for uniformity
- Some minor constification and typo fixes

Key events are handled by wxEVT_CHAR instead of wxEVT_KEY_[UP|DOWN]. Fixed issue of chars that require modifiers (e.g. ? is Shift+/ on US keyboard layout).

Hot keys specific to a tool have priority over global hot keys (TOOL_ACTION scope: AS_GLOBAL/AS_CONTEXT is finally handled properly).

Items that may be modified using EDIT_POINTs used to stay selected after pressing ESC (only EDIT_POINTs got away) - fixed.

Renamed [class_]drawpanel_gal.[cpp|h] to [class_]draw_panel_gal.[cpp|h] to follow current naming scheme.

Added possibility of switching tools by the right toolbar buttons, without deactivating the current tool first (previously tools did not switch if there was one active).

If tool was previously active and it is called again, it is brought to the top of the active tool stack.
It fixes issue of dragging of items that have EDIT_POINTs, when dragging was activated by hovering over an item and using hot key.

- resetting relative coordinates
- switching units
- not official: changing transparency for layers (works only for main layers, does not work on vias/pads/etc.)

Refactored code that handled zooming events.
Added PCB_RENDER_SETTINGS::Get/SetSketchMode().
PCBNEW_CONTROL reacts to hot keys changing display modes (sketch via/tracks, high contrast).

Added PCBNEW_CONTROLS for handling miscellaneous hot keys (trying to be compatible with the default hot key settings). Currently there are a lot of stubs to be filled out (in pcbnew_controls.cpp).
Handled actions:
- switching layers
- switching grids
- changing track width & via size

ROUTER_TOOL events have temporarily changed their hotkeys assignment.

!   The initial testing of this commit should be done using a Debug build so that
    all the wxASSERT()s are enabled.  Also, be sure and keep enabled the
    USE_KIWAY_DLLs option.  The tree won't likely build without it.  Turning it
    off is senseless anyways.  If you want stable code, go back to a prior version,
    the one tagged with "stable".

*   Relocate all functionality out of the wxApp derivative into more finely
    targeted purposes:
    a) DLL/DSO specific
    b) PROJECT specific
    c) EXE or process specific
    d) configuration file specific data
    e) configuration file manipulations functions.

    All of this functionality was blended into an extremely large wxApp derivative
    and that was incompatible with the desire to support multiple concurrently
    loaded DLL/DSO's ("KIFACE")s and multiple concurrently open projects.
    An amazing amount of organization come from simply sorting each bit of
    functionality into the proper box.

*   Switch to wxConfigBase from wxConfig everywhere except instantiation.
*   Add classes KIWAY, KIFACE, KIFACE_I, SEARCH_STACK, PGM_BASE, PGM_KICAD,
    PGM_SINGLE_TOP,
*   Remove "Return" prefix on many function names.
*   Remove obvious comments from CMakeLists.txt files, and from else() and endif()s.
*   Fix building boost for use in a DSO on linux.
*   Remove some of the assumptions in the CMakeLists.txt files that windows had
    to be the host platform when building windows binaries.
*   Reduce the number of wxStrings being constructed at program load time via
    static construction.
*   Pass wxConfigBase* to all SaveSettings() and LoadSettings() functions so that
    these functions are useful even when the wxConfigBase comes from another
    source, as is the case in the KICAD_MANAGER_FRAME.
*   Move the setting of the KIPRJMOD environment variable into class PROJECT,
    so that it can be moved into a project variable soon, and out of FP_LIB_TABLE.
*   Add the KIWAY_PLAYER which is associated with a particular PROJECT, and all
    its child wxFrames and wxDialogs now have a Kiway() member function which
    returns a KIWAY& that that window tree branch is in support of.  This is like
    wxWindows DNA in that child windows get this member with proper value at time
    of construction.
*   Anticipate some of the needs for milestones B) and C) and make code
    adjustments now in an effort to reduce work in those milestones.
*   No testing has been done for python scripting, since milestone C) has that
    being largely reworked and re-thought-out.