Remember what step modifies and reconstruct modified state on undo relative last saved
Note: SetModified must be called before SaveUndoStep

Based on TortoiseSVN revision 24215

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
When saving, copy the file parameters first and remove 'using': never use that in a header file

Based on TortoiseSVN revision 24217, 24219

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
On XP: Save the left view if it's the only one modified. Save all views if more than one is modified

Based on TortoiseSVN revision 24218

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>