New testing framework

[danielfernandez]

Thymeleaf should have a new testing framework, able to --at least--:

• Test specific fragments of code
• Handle fragment and result in the same page
• Allow the specification of the template mode to be used in the test (maybe by file name?)
• Allow other needed metadata (mainly resolution info), also in file name
• Allow the definition of a test just by creating the template (with the included result), no Java
• Offer a domain model for all tests, with some objects populated with data alread present in every context being used for evaluation.

[danielfernandez]

Done: https://github.com/thymeleaf/thymeleaf-testing