small update to man page now that we have encryption support directly
fix syntax in Makefile that Debian systems arent happy with
symlink instead of hardlink the 'latest' files

no real difference except rdiff-backup (and probably some other
software) doesn't handle hardlinks properly so doing it this way
should prevent problems with that.
resolve issue #4
cleanup repeated code to keep it DRY
update documentation for commit 92431eb6f89f6592
fix typo in readme
fix typo on man page
use "command" instead of "which"
use a temporary directory for logs and password files
make some more variables readonly
bump version number
Merge branch 'develop'