Fixing formatting errors

The usage of spaces instead of tabs causes the highlighting to display incorrectly on the docs.silverstripe.org site. I replaced them with tabs as they should be
Merge pull request #1286 from ss23/patch-4

Fixing formatting errors
FIX Respect previous tab choices in CMS on load

Previously only worked on ajax interactions.
This makes it much easier to default the CMS to
the "list view" rather than "tree view".
Tab state overrides by class or HTML5 history state

Necessary to switch from tree view to list view programmatically,
which reloads the whole tabset and needs to enable the "list" tab.
Used for the new "Show list as children" functionality in the cms.

Conflicts:
	admin/javascript/LeftAndMain.js