* remote: move get_file_checksum() into tree
* makes RemoteTree and RepoTree consistent with regard to checksum
calculation
* remote: save() now takes explicit tree parameter
* when tree is remote.tree, save will be a move + link operation
(same as default existing behavior)
* when saving path from a different tree, save will be a copy operation
* tests: update for moved remote/tree functions
* remote: move get_checksum into tree
* remote: separate cloud remote and cache classes
* tests: update unit tests for remote/cache separation
* remote: cloud cache should extend cloud remote
* remote: move LocalRemote.get
* tests: update func tests
* dependency: update for moved get_checksum
* remote: fix state lookup bug