TextBody.Text MessageBody.IsTruncated attributes not captured

[gautamsi]

Fix in MessageBody.LoadFromXmlJsObject, bug found by #143

[gautamsi]

IsTruncated is not captured as of now. Will re look when porting beyond 2.0 version of ews managed api. targeted 2.0 for ews-javascript-api

[gautamsi]

pushed to backlog, IsTruncated property is introduced in later version of exchange (not in the snapshot used to port this) which will be ported after 1.0