* Complete comment translation for all EESchema source files.
* Complete comment translation for all 3D viewer source files.
* Rename class class_hierarchical_PIN_sheet to SCH_SHEET_PIN.
* Rename class DrawSheetStruct to SCH_SHEET.
* Tool tip capitalization fixes.
* Uncrustify and spell check comments and strings in all modified source
files.
* Component library objects renamed for improved readability.
* Fields now move when selected in library editor.
* Add copy constructor to all library draw and library component objects.
* Added copy constructor to EDA_BaseStruct.
* Delete base screen in WinEDA_DrawFrame destructor to prevent potential memory leak.
* Fixed memory access bug when replacing and adding a component to library.
* Moved library component block manipulation code into component object.
* Removed all of the global variables used by the library editor main window object.
* The usual code cleaning and refactoring.