Implement deferValidation.

[mshima]

Implement deferred validation. This allows to generate jdlObject without validation. Validation will be done after.

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[MathieuAA]

I'd rather remove validation from JDLObject to make it more stupid. Validation can be done by the BusinessErrorChecker.

[MathieuAA]

The flow is:

• JDL content is parsed
• The document parser creates a JDL object
  • This object doesn't validate
• the Business error checker validates
• etc.