Feature/validation decorators

[memicmiralem]

Fixes #45

Proposed Changes

• adds new flag useValidation: boolean (default = false)
• if the flag is true then validation decorators are generated similar to swagger decorators

[bennet-esyoil]

Suggested change

	case 'Int':
	decoratorArgs.name = 'IsInt'
	break
	case 'BigInt':
	decoratorArgs.name = 'IsInt'
	break
	case 'SmallInt':
	decoratorArgs.name = 'IsInt'
	break
	case 'Int':
	case 'BigInt':
	case 'SmallInt':
	decoratorArgs.name = 'IsInt'
	break

you could use use a fall-through here, making it easier to read. Otherwise a fixed map at the top of the file would also be better to not have this huge switch-case here, have a look at the primitiveMapType variable