Removed an old, unneeded comment.
Enter Key sample corrections.
Fixed enter key sample
Fixes #68. Removed invalid code.
Minor corrections in the Enter Key sample.
Fixes: #79: Adjusted font in sample drop-downs to sample text.
Source code for UI Languages sample corrected.
Replaced accordion arrows with +/- symbols. Minor sidebar adjustments.
Made H3 font weight normal. Adjusted submenu list font size.
Enlarged +/- symbols in the sidebar.
Used active item style from ckeditor.com.