Fixes issue #67.
As per dist spec, DELETE of a image manifest can only be done with
digest as <reference> param. Previously, tags were being allowed as
well. This is not conformant to the spec.
dist-spec compliance tests are now becoming a part of dist-spec repo
itself - we want to be compliant
pkg/api/regex.go:
* revert uppercasing in repository names
pkg/api/routes.go:
* ListTags() should support the URL params 'n' and 'last'
for pagination
* s/uuid/session_id/g to use the dist-spec's naming
* Fix off-by-one error in GetBlobUpload()'s http response "Range" header
* DeleteManifest() success status code is 202
* Fix PatchBlobUpload() to account for "streamed" use case
where neither "Content-Length" nor "Content-Range" headers are set
pkg/storage/storage.go:
* Add a "streamed" version of PutBlobChunk() called PutBlobChunkStreamed()
pkg/compliance/v1_0_0/check.go:
* fix unit tests to account for changed response status codes
