Added unit test class for ArrayDeclaration sniff.
Added unit test class for ValidClassName sniff.
Added unit test class for FileName sniff.
Added unit test class for MultipleStatementAlignment sniff.
Added unit test class for FunctionCallSignature sniff.
Added unit test class for FunctionDeclarationArgumentSpacing sniff.
Added unit test class for ValidFunctionName sniff.
Added unit test class for ObjectInstantiation sniff.
Added unit test class for DiscouragedFunctions sniff
Added unit test class for DoubleQuoteUsage sniff.
Added unit test class EscapeOutput sniff.
Added unit test classes related to WhiteSpace sniff.
Added instruction to run the tests and conventions used for writing unit test.
Update README to note how to just run WordPress tests

See @gedex: https://github.com/x-team/WordPress-Coding-Standards/pull/27#issuecomment-15592466
Merge pull request #27 from x-team/unit-tests

Unit tests