Issue #88 [BuildQueue] - added get_item_by_id

This method is used to obtain details about a queue item if the ID is known
Add logging for Client#get_root
Issue #88 [Client] - Client#api_post_request update

This method now accepts a third parameter (raw_response) just like
api_get_request which is used to determine whether to return the raw response
or to return just the response code. This raw response will then be used to
obtain the 'location' header from the build POST response to obtain the task
queue ID
Issue #88 [Job] Initial WIP code towards obtaining build number
Remove duplicate "/" when making view api request
Issue #88 Fixed unit tests because of the changes
Issue #88 - Added some documentation
Issue #88 - Fixed the logic

* It handles cases where the job is already in the queue and concurrent builds
are disabled. Jenkins usually responds with the job's URL as the location
header and hence the queue number will not be available.
Merge pull request #94 from arangamani/get_build_number

Get build number