Add Indent and Outdent commands for WYSIWYG

Some say that SCE sukz because you can't nest lists while in WYSWIYG. Well, now you can.

Tested with the BBCode plugin and it works (does not work when not in WYSIWYG)
Some improvements to cope with the naughty IE rules  (<blockquote>) that others followed
Indent only for lists for now

After a lot of searching, it's better not to have an indent, at least, until we have some nice amount of study.
Until then, let's just have the indent to allow nesting of lists.
I've made an extensive list of tests to make sure this would cover all the situations with IE10, Firefox 23 and chrome 28. I think I have all covered.
Fixed spaces problem
Merge pull request #190 from brunoais/1.4.5-dev

Add Indent and Outdent commands for WYSIWYG