[TASK] Switch to namespaces

Should be done now. However, core bugs have been detected while migrating these ViewHelpers and making aliases:

http://forge.typo3.org/issues/54115

Which means using this branch will still throw Exceptions unless templates are migrated to contain ``{namespace flux=FluidTYPO3\Flux\ViewHelpers}`` instead of ``{namespace flux=Tx_Flux_ViewHelpers}``. When core bugfix is merged, no such migration will be necessary.