Make Share API more RESTful

Require share name as part of the url in post and delete requests. Leave POST
idempotence as an input error so it appears clearly as an input error for the
user when trying to create a share with duplicate name.
Update share cli urls to comply with backend change

Share API has become RESTful. Update the url and supporting code in the share
cli for create, list and delete operations to work with the new backend change
Update share urls in the WebUI

Share API has become RESTful. Update the create and delete urls to add share
name as part of the url.
Merge pull request #29 from schakrava/issue#10_share_idempotence

Issue#10 share idempotence