Updated pom metadata, dependencies, and overall layout

Updated dependencies to be more consistent with that of other Jenkins
plugins (using Jenkins specific, rather than Hudson).
Created gitignore file
Code formatting cleaning and removing methods that aren't used.
More formatting changes
Removed unneeded private constructor
Refactored out the tweet message building into a TweetBuilder interface
Created a TweetDeliverer interface with implementation and test case
Created LinkGenerator interface, implementation, and test case
Little bit of refactoring on the TweetBuilder to pull out common code
Moved the updateTwit into the Publisher - trying to clean up Descriptor
Added commons-codec
Added descriptors to the Builders since Build results weren't being set

Not quite sure why they weren't being set. For the Aborted build, it
reported a status of FAILURE. After looking at the FailureBuilder and
noticing that it has a Descriptor, added them to these builds.
Added a README file
Added changelog info to the README
Merge pull request #2 from jenkinsci/develop

Twitter4J 3.0.3 update and started some refactoring