enabled 'refchk' command

- Quote $RECURSE_PATH in 'find' command in recurse_path()
- Added DRY_RUN variable with a default of 0 (don't do a dry run)
- Rename GIT_CMD to GIT_TOOL_CMD so that individual functions can use GIT_CMD
  for their own purposes, and so as to not confuse people reading the script
- Show the repo path being searched when the script first runs
- Fixed the FSF snailmail address