Added support for unique constraints
Updated tests
Adding collection handling for identity return

Adds the ability for the 'Return(identity)' overload to cope with
collections.
Adding code review changes
Binary Expressions (== and !=) handled in Return

Return statements now handle == and != for null elements.
Update to the location of the message const

And a quick word change.
Merge pull request #28 from cskardon/issue-27

(Issue 27) Binary expressions in the return statement.
Merge pull request #25 from cskardon/issue-24

Adding collection handling for identity return
Renamed constraint methods
Merge pull request #23 from sbarski/master

Added support for Constraints to Cypher
added support for Cypher REMOVE
Merge pull request #32 from bossie/cypherremove

added support for Cypher REMOVE
Detects when a MemberExpression returns null and adjusts it as a ConstantExpression

Neo4j doesn't consider null as valid values for PropertyBags
(relationships and nodes).
Neo4jClient could have a MemberExpression in a Where() construct and it
could detect it if was in reality a ConstantExpression, however it just
sends the value as parameter regardless if it's a null value.

This commit fixes that by having the same behavior that occurs in
VisitConstant(ConstantExpression) if it detects a null value.
Added unit tests for CypherWhereExpressionVisitor.VisitConstantMember()

The unit tests from the last commit was moved from the
CypherFluentQueryWhereTests to CypherWhereExpressionBuilderTests and added
three more unit tests for all logic branches within this method.
Merge pull request #38 from arturosevilla/nullinmemberexpressionfix

Detects when a MemberExpression returns null and adjusts it as a ConstantExpression
Struct in Expression<> throws ArgumentException

Although C# doesn't allow a struct to have a parameterless constructor,
internally the CLR allows it, and I suspect that's why there is no error
when building an Expression when calling a non-existent parameterless
constructor for a struct.

The added coded protects against NullReferenceExceptions which occurred
when the Expression (MemberInitExpression and NewExpression) contained
such non-existent constructors.
Merge pull request #39 from arturosevilla/structinreturnexpression

Struct in Expression<> throws ArgumentException
Neo4J Batch Insert Exceptions made visible
Checked Neo4j exception response for null
Merge pull request #40 from bholdt/master

Neo4J Batch Create Exceptions made visible