Remove unused error functions

lib/errors.js

@@ -18,18 +18,6 @@ let Errors = {
 		}
 
 		return [`${param} is invalid${punctuatedMessage}`, 400]
-	},
-	missingParameter (param) {
-		return [`Missing ${param}`, 400]
-	},
-	invalidParameterType (param, type) {
-		return [`${param} must be of type ${type}`, 400]
-	},
-	parameterLengthTooSmall (param, length) {
-		return [`${param} must be more than ${length} characters in length`, 400]
-	},
-	parameterLengthTooLarge (param, length) {
-		return [`${param} must be less than ${length} characters in length`, 400]
 	}
 }