Implement partial cache invalidation
Merge changes
Support creating and modifying files
Implement file unlinking
Distinguish unlink/rmdir; rename .cached_file/dir -> .inode; fix bug in CachedDirInode
Implement mkdir
Fix bugs in CachedFileInode unlinking
Reset log level
Fix bugs in closing unlinked files
On full invalidation, explicitly unlink open cacheinodes
Fix conflation between deleted cache files due to invalidation and unlinking
Upload files and mkdir using parent directory dircaps rather than full paths to avoid Tahoe doing uncached directory lookups
Add cached data lifetimes for read and write operations
Modify cache metadata in-place rather than first uploading and then downloading it
Do not block on CachedFileInode.get_size --- rather, return the current size
Delete files by dircap, not by full path
Use a separate connection pool for PUT requests