Merge pull request #129 from geoffgarside/freebsd-stable-etc-dir

Set the FreeBSD /etc/salt dir to PREFIX/etc/salt
Add first pass attempt at adding remote URL to -c

If the -c argument is given an HTTP or FTP URL then the file will be
downloaded, extracted if neccessary, and the new path returned to
ensure that the TEMP_CONFIG_DIR has a sane location.
Change some of the paths used for config extraction.
Move TEMP_CONFIG_DIR existence check back
Add debug echos to __check_config_dir
Add more debug
Change return to echo in __check_config_dir
Remove echos as they'll be interfering with execution.