PATCH: regedit: implement LoadSettings(), SaveSettings()

Created an attachment (id=7416)
PATCH: regedit: implement LoadSettings(), SaveSettings()

Patch makes ROS regedit to load/save settings as win2k3 regedit does.
Tested on win2k3 and ROS r55736. Works on both systems fine. The patch makes regedit to save/load settings for:
window placement;
listview columns size;
last opened key;
status bar;
splitter.

Patch by Grégori Macário Harbs and Edijs Kolesnikovičs.