Updated list of features in README
Merge pull request #14 from robru/master

Time Machine style backup pruning.
Merge branch 'master' of https://github.com/laurent22/rsync-time-backup
Removed old backup deletion prompt, and formatting tweaks.

- Removed old backup deletion prompt as it's not really needed.
- Made all variables uppercase for consistency.
- Used double square brackets in `if` statements.
Rebase on master.