* Replace all occurrences of the word "part" with "unit" when referring to
multiple unit components for improved consistency.
* Replace "shared by" with "common to" when referring to objects (lines, arcs,
pins, etc.) that are common to all units.
* Improve wording in library component properties dialog.
Eeschema: Viewlib is now accessible from Libedit (to browse libs or load a component to edit)
Libedit: uses now the same dialog as the schematic editor to load a component
Some code cleaning.