added ValidationBuilder

• added "autoload-dev" to composer.json (thank you @ordago)
• added missing extension "ext-json" to composer.json (thank you @ordago)

• use SchemaInterface instead of Schema in StrictValidationFromSchema and ValidationFromSchema
• added validator expectKeyToBeObject() and expectKeysToBeObject()

• introducing schema which add a new way to define your validations structure
• added Schema, SchemaInterface, SchemaCompiler and SchemaCompilerInterface
• added ArrayValidationExceptionInterface to help catching any validation exceptions
• added StrictValidationFromSchema
• rewritten StrictValidation and added AbstractValidation
• added Validation, ValidationFromDefinition and ValidationFromSchema
  which act almost like as Strict* classes but without exceptions
• fixed bug with ValidationDefinition where same method validation were not stacked but overwritten
• added ValidationDefinitionExecutor

• [BC] renamed method expectNElement() to expectNKeys() in ArrayValidation
• added expectNKeys() and expectOnlyOneFromKeys() to StrictArrayValidator
• added interfaces ArrayValidationInterface and ArrayValidatorInterface
• [BC] renamed all classes and interfaces with better name
• added ValidationDefinition and StrictValidationFromDefinition

• added methods expectKeysToBeArray(), expectKeysToBeBoolean() and expectKeysToBeFloat() to StrictArrayValidator
• transformed ArrayValidationException to 2 more specific exceptions: InvalidStructureException and InvalidTypeException
• [BC] simplified and reordered constructor params of StrictArrayValidator

Initial release