Adopt namespace for TYPO3 10

[Georg Ringer]

The namespace of

TYPO3\CMS\Fluid\Core\ViewHelper\AbstractTagBasedViewHelper;

must be changed to

use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractTagBasedViewHelper;

furthermore the class

@throws \TYPO3\CMS\Fluid\Core\ViewHelper\Exception

seems not to exist, so this can be removed as well

‌

[Markus Klein]

[FEATURE] Add compatibility for TYPO3 v10 API

Fixes: #14

→ <<cset af734ccf013a>>