Replace vtkFreeType(Tools|Utilities) with vtkTextRenderer.

This patch replaces most of the remaining calls to the vtkFreeType
text rendering classes with equivalents that go through the
vtkTextRenderer layer. Most of these were used to calculate bounding
boxes for text actors, which would be incorrect if the text actor was
rendering math text.

Also removed a few unneeded headers and mentions of vtkFreeType.

Change-Id: Iddf7d84dbf46c30774baf96d32edd07b6da77031
Merge topic '13484-MathTextPdfExport' into master

3b3130eb Replace vtkFreeType(Tools|Utilities) with vtkTextRenderer.