Dev: 1b3725a3

[cypher]

• Use parentheses at operators that might be affected by precedence.
• With syntax for 3, 4 and 5 expressions.
• Syntax for null expression.

[apoc]

• ValidateException: helps to extract errors thrown by apoc.util.validate procedure.
• Changes to when and case syntax.
• Support apoc.do.when and apoc.do.case calls.
• Fixes for type overprecision.