v4.0

• Added "xor" checksum algorithm
• New validateMinLength property of the <message>
• New defaultValidValue property of the <int> field.
• New availableLengthLimit property of the <int> and <enum> fields.
• Allow copyFieldsFrom property of the <message> and <interface> to specify reference to a <bundle> field.
• New code overriding properties (readOverride, writeOverride, refreshOverride, lengthOverride, validOverride, nameOverride) for any field and message definition.
• Improvements to the existing documentation (See #2 and #4).