Add endpoint for deleting workspaces; fixes 60887336
update response after creating a node to include the full URI to the
created resource; fixes #60887246
After creating a new workspace, return the path to the workspace in the location header. Fixes #60886000
Support HTTP preconditions for DELETE and MOVE operations

fixes #60884508
Support checksums when modifying content at fcr:content

Fixes #60875916
replace fcr:identifier?numPids parameter with 'count'

fixes #60877478
Merge pull request #156 from futures/http-fixes

HTTP API fixes
Resolves:
https://www.pivotaltracker.com/story/show/60887336
https://www.pivotaltracker.com/story/show/60887246
https://www.pivotaltracker.com/story/show/60886000
https://www.pivotaltracker.com/story/show/60884508
https://www.pivotaltracker.com/story/show/60875916
https://www.pivotaltracker.com/story/show/60877478