Translation of interface, removing button and grippie

Hi,

Here is a quick patch which fixes some user interface issues:

• Makes the "Switch to Plain Editor" / "Switch to Rich Text Editor" buttons translatable.
• Added some space between the Switch button and the Editor, cleaning up the looks.
• Removed the "grippie" used to resize the text field which is not working with the Rich Text Editor turned on
• Removed the "Split summary at cursor" button which have been bugging me for a while, which does not work with RTE turned on.
• The grippie and split summary button will become visible when switching to plain text mode

Unfortunately I am very new to the CVS system, so the changes i made in issue #250245: When switching back to Rich Text Editor, no changes are saved. are still left in there. I hope you can bare with me.