Add new VendorOption truncateLabelEnabled

Because of my lack of experience with git, comments about my commits are misleading.
15 Dec commit includes
- add of truncateLabelEnabled vendor option in gt-render package
- small fixes to make geotools tests compilable on a windows machine with accented characters in the path

18 dec commit includes
- addition of unit tests for truncateLabelEnabled options (1 java file + 12 resources)

(document for licence issues will follow)

Michaël