correct cursor movement accross lines & zero width things

git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@108 0fc631ac-6414-0410-93d0-97cfa31319b6

src/render/text/viewer.hpp

@@ -79,6 +79,8 @@ class TextViewer {
 	/// Is the character at the given index visible?
 	bool isVisible(size_t index) const;
 	/// Find the first character index that is at/before/after the given index, and which has a nonzero width
+	/** More precisely: it returns a position so that no character after it has zero width
+	 */
 	size_t firstVisibleChar(size_t index, int delta) const;
 	
 	/// Return the height of the last line