Modified guessDefaultEscapingStrategy to not escape txt templates

Useful for plaintext emails.
Merge branch '2.2' into 2.3

* 2.2:
  Teardown used wrong property
  Modified guessDefaultEscapingStrategy to not escape txt templates
  Fix DateType for 32bits computers.
  Fixed the registration of validation.xml file when the form is disabled
  When getting the session's id, check if the session is not closed