Initial install commit.

What works:
-simple file to file destination install
-multiple files to folder destination install
- -t flag
- partially -m flag, right now accepts mode only on form [ugoa]+[+-=][rwx]+, but in current state should be relatively easy to expand

Any feedback is welcome, some parts of the code are ugly even for me.
You can simplify some of this code by making the return type `IoResult<()>` (this would require you to do `use std::io::IoResult` at the top of the file).  By doing so you can change the `match fs::copy(...) { ... }` into `try!(fs::copy(...))`, as well as the `chmod` below that.