Style a bit the code

Fix for issue crlcu#58 - Using optgroups breaks keepRenderingSort

Change the behaviour of hide/show functions only if browser is IE

Move all - bugfix for IE and Safari

Set as version 2.2.4

Make search case insensitive

submitAllRight bugfix (issue 40)

Change the approach for search

Update documentation to match with the changes made in v2.2.0

Hide options when search bugfix 2