Eeschema enhancements: Option to annotate keeping multi-unit parts grouped and friendlier warning for modifying power values.

Very minor fixes: 3D viewer: remove artifacts with NPTH pads having the save size as their hole. Kicad: remove duplicate submenu in menubar. remove a minor coverity warning

Make hotkey string info translatable in dialogs. These strings are now prefixed by _HKI , which can be used by translation tools to extract them.

Fix Bug #1426675 (Undo and cancel commands don't have effect for Duplicate operation in legacy mode)

Plot pdf: fix issue when a 0 sized text is plotted (files are broken): now 0 sized texts are ignored.
pcbnew: remove a false error message when undoing a change on a text, or some other board items (graphic items for instance)

they are now shown only when a new board is loaded, if there are warnings.

Try to fix Bug #1431765 (Pcbnew crashes in GAL when entering 3d display when a board outline is not closed)
This change modify the way warning messages are displayed: now the are displayed outside a paint event.

Fix a not shown dialog (sheet pin dialog editor) under XFCE and Unity. Make "display hotkeys list" window not modal.
As usual, fix a few minor coverity warnings

Cvpcb: Shows a better message when a netlist is not found.

Try to fix Bug #1431391 (Unable to edit pins in Schematic library editor). It happens on XFCE, but also on Unity. This fix works on Unity. (it is due to the fact the dialog is not raised, for an unknown reason, and this bug depend on the way Eeschema and Libedit are run).
Add Ctrl+E hotkey in eeschema to edit a component with Libedit (similar to pcbnew Ctrl+E hotkey)
As usual, fix a few minor coverity warnings

Remove a few coverity warnings. Fix some comments which were incorrect, due to the changes in code. Remove not compiled code (kept as comments), now outdated or useless
legacy plugin: better compatibility with old brd files (current track width and current vias size, stored in SETUP section, were not read from file and incorrectly set)

Eechema, libedit, pin dialog editor: show pin texts  in pin  preview canvas.

Fix minor bug #1429990 (3D viewer shows hidden footprint graphic texts ). Fix minor coverity warnings (not initialized members and dead code)

class PLOTTER: dash lines parameters in one place for plot. I made minor changes (values in mm and set to give the same size as dashed lines drawn by wxDC, using short dash.)

Fix a few minor coverity warnings.

Moved "Place Target" and "Place Module" tools from DRAWING_TOOL to PCB_EDITOR_CONTROL (to avoid placing modules in the footprint editor).