First commit
Beginnig of create of RmOlder + UnitTests
Implements 2 methods find+is_too_old

fn find(&self, predicate: |path:&Path| -> bool) -> Vec<Path>
fn is_too_old(&self, file_age: u64) -> bool
Implements run and inner_run methods + Add rustdoc
Add --dry option to command line
Add a TODO file
Command line arguments are now parsed by Args