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.
* Fix parent of elements in wxSizers.
* Update old dialog with recent version of wxFormBuilder.
* Add wxALIGN_CENTER_VERTICAL flag to some dialogs.
* Update wxFormBuilder timestamp in generated sources.
* 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.
