Fix timezone issues in EwsUtilities and ExchangeServiceBase.

Timezone should be set to UTC explicitly to work on systems with non-UTC timezone.
Remove unused methods from ServiceRequestBase.

- ServiceRequestBase.emit() is unused.

- ServiceRequestBase.endGetEwsHttpWebResponse() is unused, but also
  incorrect: Why would one compare an HTTP status code with an enum
  ordinal?!
Remove commented call to ServiceRequestBase.endGetEwsHttpWebResponse().

Also removed a getter call without assignment and some other commented
code in SimpleServiceRequestBase that made no sense.
Enabled preemptive authentication in HttpClientWebRequest, reducing connection overhead.
Fix #62: validatePropertyAccess() in UserConfiguration is wrong

The condition for the if statement inside this method was reversed.
Merge pull request #22 from eveoh/preemptive-authentication

Enable preemptive authentication in HttpClientWebRequest
Merge pull request #27 from eveoh/unused-methods-in-servicerequestbase

Remove unused methods from ServiceRequestBase
Merge pull request #6 from eveoh/timezone-fixes

Fix timezone issues in EwsUtilities and ExchangeServiceBase
Fix #33: EwsXmlReader uses == to compare Objects
Fix #9: ExtendedPropertyDefinition.equals() is flawed
Rename XMLNodeType to XmlNodeType
Fix #31 and #32 remove useless null checks
Rewrite ExtendedPropertyDefinition.isEqualTo() for readability
Fix #11: Invalid downcast check
Merge pull request #70 from vboctor/Issue9

Fix #9: ExtendedPropertyDefinition.equals() is flawed
Remove extra semi-colons causing IntelliJ warnings
Fix spaces before semi-colons
Fix IntelliJ warning about '== false' usage
Remove unused using statements in AsyncExecutor
Remove unused fields in AsyncExecutor