Eeschema: cleaning code. Start work to enhance annotation algorithm.
Already added an option to annotate using sheet number (sheet 1 uses numbers 100 to 199, sheet 2 uses 200 to 299..).
Works fine if deleting existing annotation, but needs work to be used when the existing annotation is kept .
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.