Fixes http://youtrack.jetbrains.com/issue/VIM-287

`ChangeGroup` looks like it could be refactored to use [`com.intellij.openapi.editor.actions`](https://github.com/JetBrains/intellij-community/tree/master/platform/platform-impl/src/com/intellij/openapi/editor/actions) as there are a few other surprises like this one. [`EditorActionUtil.moveCaretToLineEnd(...)`](https://github.com/JetBrains/intellij-community/blob/master/platform/platform-impl/src/com/intellij/openapi/editor/actions/EditorActionUtil.java#L497) seems to put us exactly where we need to be after the fold, and takes into account soft-wraps etc. - `ChangeGroup.insertNewLineBelow(...)` will now behave as expected.