- Changed find_colon() into check_for_hostspec(), extending it to
understand the rsync:://HOST:PORT/PATH format, allowing all HOSTs
to be IPv6 literal addresses enclosed in '[' and ']', and changing
it to return the 3 parts of the spec separately (host, port, and
path).
- Relocated the code that handles the sanitation and validation of
the files_from arg in order to make its placement a little more
logical.
- Replaced remote_filesfrom_file with filesfrom_host, which makes
the value of the files_from variable more intuitive.