Merge pull request #3 from plivo/dev

Add server response code to de-serialized object
Merge pull request #4 from plivo/dev

Fix for number APIs
Adding call duration and bill duration values in 
the CDR attributes
Updated version to 2.3.4
The earlier logic to include server code failed in
certain cases. Fixing that.
Refactoring incoming carrier package to carrier
Adding Outgoing Carrier and Outgoing Carrier
Routing APIs
Updating version to 2.3.5
Updating jar paths.
Adding the recordWhenAlone attribute.
Updating version to 2.3.6
Updating Jar links in the README
removed unnecessary imports, and also, serialized names for api response.
xml serialization: using java classes instead of jaxb.
pom version bump: v3.0.0
updated links to latest jar files; added link for GPG public key.
verify pre-built jar with gpg key.