Fix bug in SCH_SHEET copy constructor (size not copied, so copied hierarchical sheets have a 0 size), and a minor bug in block save.

fix bug 692240: a subtle bug in LIB_COMPONENT::LocateDrawItem() that destroys DefaultTransform matrix.

Eeschema: in component properties dialog, add control for fields texts justification, like in Libedit.
Fix some Doxygen warnings.

Eeschema, Modedit: void fields (mainly the footprint field) now cannot be selected when click on them.

Eeschema: fix issues in drag command (mainly hotkey command and forgotten wire ends connected to components to drag).
 Rename EDA_Rect::Inside to EDA_Rect::Contains ( EDA_Rect::Inside( const EDA_Rect& aRect ) was very ambiguous )
 Fix some Doxygen warnings and erroneous comments; Add comments.

DIR_LIB_SOURCE.  It only needs to be able to read Sweet strings quickly.
@todo: Change public API regarding part rev string.