v0.5.0-beta

abandonded setup utils and requirements txt files, just use setup.py directly
added some further command help to the README
implemented rm command
raise error if unsupported recursive option is used
implemented reconstruct option for cp command
bugfix - ignore softsync manifest file in directory listing
bugfix - don't do any filesystem changes if dry run
tweaked API - replaced Roots class with static parse_roots method
refactored around pathlib and introduced initial "file://" StorageScheme delegate
fixed up root semantics: raise error if relative path escapes a root
renamed command methods to have 'softsync' in the names
added support for programmatic usage