This changes the containing dir name to match the fileutils package name.

This simplifies logging and logging/exiting, plus supports the -v flag
for showing verbose output.

A lot has changed to the previously named codegangsta/cli library, and
this gets up to date with everything, fixing issue #8.

It also passes around errors from funcs that perform actions inside the
command funcs, for more Go-ness.

- Adds comments where necessary
- Fixes some variable names
- Fixes if/else statements with returns
- Use fmt.Errorf(...)

When composing posts with `writeas new`, this is checked before `EDITOR`
and then falling back to default editors.

Plus add download + license badges

Would previously only work for `writeas post --code` command.

Backend now supports a cipher suite Go is compatible with.