Replace all instances of "component" and "part" with "symbol" when
referring to schematic and library symbols.
Replace all instances of "component" with "footprint" when referring to
board and library footprints.
Minor dialog layout fixes to some of the dialogs impacted by the UI
string changes.
* 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.